Abdollahi, Farnaz; Kenyon, Robert V.; Patton, James L.
Background In spite of their importance to everyday function, tasks that require both hands to work together such as lifting and carrying large objects have not been well studied and the full potential of how new technology might facilitate recovery remains unknown. Methods To help identify the best modes for self-teleoperated bimanual training, we used an advanced haptic/graphic environment to compare several modes of practice. In a 2-by-2 study, we compared mirror vs. parallel reaching move...
Takiyama, Ken; Sakai, Yutaka
Motor learning in unimanual and bimanual planar reaching movements has been intensively investigated. Although distinct theoretical frameworks have been proposed for each of these reaching movements, the relationship between these movements remains unclear. In particular, the generalization of motor learning effects (transfer of learning effects) between unimanual and bimanual movements has yet to be successfully explained. Here, by extending a motor primitive framework, we analytically proved that the motor primitive framework can reproduce the generalization of learning effects between unimanual and bimanual movements if the mean activity of each primitive for unimanual movements is balanced to the mean for bimanual movements. In this balanced condition, the activity of each primitive is consistent with previously reported neuronal activity. The unimanual-bimanual balance leads to the testable prediction that generalization between unimanual and bimanual movements is more widespread to different reaching directions than generalization within respective movements. Furthermore, the balanced motor primitive can reproduce another previously reported phenomenon: the learning of different force fields for unimanual and bimanual movements.
Blinch, Jarrod; Cameron, Brendan D; Franks, Ian M; Carpenter, Mark G; Chua, Romeo
Symmetric, target-directed, bimanual movements take less time to prepare than asymmetric movements (Diedrichsen et al. in Cerebral Cortex 16(12):1729-1738, 2006; Heuer and Klein in Psychol Res 70(4):229-244, 2006b). The preparation savings for symmetric movements may be related to the specification of symmetric amplitudes, target locations, or both. The goals of this study were to determine which symmetric movement parameters facilitate the preparation of bimanual movements and to compare the size of the facilitation for different parameters. Thirty participants performed bimanual reaching movements that varied in terms of the symmetry/asymmetry of starting locations, movement amplitudes, and target locations. Reaction time savings were examined by comparing movements that had one symmetric parameter (and two asymmetric parameters) to movements with all asymmetric parameters. We observed significant savings (~10 ms) for movements with symmetric amplitudes and movements with symmetric target locations. Reaction time costs were examined by comparing movements that had two asymmetric parameters (and one symmetric parameter) to movements with all symmetric parameters. We observed significant reaction time costs (~13 ms) for all movements with asymmetric amplitudes. These results suggest that movement preparation is facilitated when amplitudes or target locations are symmetric and that movement preparation suffers interference when amplitudes are asymmetric. The relative importance of the three parameters to movement preparation, from most to least important, is movement amplitudes, target locations, and then starting locations. Interference with asymmetric amplitudes or target locations may be caused by cross-talk between concurrent processes of parameter specification during response programming. PMID:25388127
Kantak, Shailesh; McGrath, Robert; Zahedi, Nazaneen
Coordination during goal-directed movements emerges from an interaction of task and individual constraints. It is not known how individuals with unilateral stroke and age-matched controls coordinate their arms when performing symmetric and asymmetric movements to accomplish common task goals compared to independent task goals. Eleven individuals with chronic stroke and ten age-matched controls executed a bimanual task under virtual conditions that allowed systematic manipulation of symmetry and goal conditions. Spatial and temporal bimanual coordination was characterized using the cross-correlation coefficients and time lag between the tangential velocities between the two hands. While task conditions had little effect on coordination of control participants, individuals with stroke were less coordinated in space and time during common-goal bimanual actions employing asymmetric arm movements. Further, patients demonstrated lesser contribution of their paretic arm compared to their non-paretic arm during common-goal conditions. These findings indicate that conceptualization of task goals (common vs. independent) and symmetry of arm movements influence coordination and contribution of the two hands during bimanual tasks in patients with stroke. PMID:27180035
Rudisch, Julian; Butler, Jenny; Izadi, Hooshang; Zielinski, Ingar Marie; Aarts, Pauline; Birtles, Deirdre; Green, Dido
Children with unilateral Cerebral Palsy (uCP) experience problems performing tasks requiring the coordinated use of both hands (bimanual coordination; BC). Additionally, some children with uCP display involuntary symmetrical activation of the opposing hand (mirrored movements). Measures, used to investigate therapy-related improvements focus on the functionality of the affected hand during unimanual or bimanual tasks. None however specifically address spatiotemporal integration of both hands. We explored the kinematics of hand movements during a bimanual task to identify parameters of BC. Thirty-seven children (aged 10.9±2.6years, 20 male) diagnosed with uCP participated. 3D kinematic motion analysis was performed during the task requiring opening of a box with their affected- (AH) or less-affected hand (LAH), and pressing a button inside with the opposite hand. Temporal and spatial components of data were extracted and related to measures of hand function and level of impairment. Total task duration was correlated with the Jebsen-Taylor Test of Hand Function in both conditions (either hand leading with the lid-opening). Spatial accuracy of the LAH when the box was opened with their AH was correlated with outcomes on the Children's Hand Use Experience Questionnaire. Additionally, we found a subgroup of children displaying non-symmetrical movement interference associated with greater movement overlap when their affected hand opened the box. This subgroup also demonstrated decreased use of the affected hand during bimanual tasks. Further investigation of bimanual interference, which goes beyond small scaled symmetrical mirrored movements, is needed to consider its impact on bimanual task performance following early unilateral brain injury. PMID:26803675
Kagerer, Florian A
Interactions between the hands are a collateral of simultaneous bimanual movements and can inform us about the functional asymmetries of the dominant and nondominant hemisphere-effector systems. Few studies on bimanual coordination have focused on discrete movement control, and even fewer have looked at this in the context of handedness. Using a novel bimanual paradigm in which both hands perform simultaneous target-directed movements, this study addressed interference between the hands in two groups of left-handed individuals. In one group, the dominant hand was perturbed, and in the other, the nondominant hand; the respective contralateral hand moved without visual feedback. Results show that the kinematic perturbation of the dominant left hand resulted in directional interference in the nonvisible right hand. Similarly to previous studies using this bimanual paradigm, interference became manifest through isodirectional deviations in the nonvisible hand in the majority of participants. The findings mirror the results of a previous study in right-handers. At the same time, interference was overall weaker in the left-handers, and not as exclusively dominant to nondominant as in the previous right-handed sample. The results not only confirm that hand control characteristics switch with handedness, but also shape interactions between the hands accordingly in left-handers. PMID:26821317
Full Text Available Stroke patients recover more effectively when they are rehabilitated with bimanual movement rather than with unimanual movement; however, it remains unclear why bimanual movement is more effective for stroke recovery. Using a computational model of stroke recovery, this study suggests that bimanual movement facilitates the reorganization of a damaged motor cortex because this movement induces rotations in the preferred directions (PDs of motor cortex neurons. Although the tuning curves of these neurons differ during unimanual and bimanual movement, changes in PD, but not changes in modulation depth, facilitate such reorganization. In addition, this reorganization was facilitated only when encoding PDs are rotated, but decoding PDs are not rotated. Bimanual movement facilitates reorganization because this movement changes neural activities through inter-hemispheric inhibition without changing cortical-spinal-muscle connections. Furthermore, stronger inter-hemispheric inhibition between motor cortices results in more effective reorganization. Thus, this study suggests that bimanual movement is effective for stroke rehabilitation because this movement rotates the encoding PDs of motor cortex neurons.
Calvin, Sarah; Huys, Raoul; Jirsa, Viktor K.
Simultaneously executed limb movements interfere with each other. Whereas the interference between discrete movements is examined mostly from a cognitive perspective, that between rhythmic movements is studied mainly from a dynamical systems perspective. As the tools and concepts developed by both communities are limited in their applicability to…
Full Text Available Parkinson's disease (PD is a neurodegenerative disorder affecting middle-aged and elderly people. PD can be viewed as "circuit disorder", indicating that large scale cortico-subcortical pathways were involved in its pathophysiology. The brain network in an experimental context is emerging as an important biomarker in disease diagnosis and prognosis prediction. This context-dependent network for PD and the underling functional mechanism remains unclear. In this paper, the brain network profiles in 11 PD patients without dementia were studied and compared with 12 healthy controls. The functional magnetic resonance imaging (fMRI data were acquired when the subjects were performing a pseudorandomized unimanual or bimanual finger-to-thumb movement task. The activation was detected and the network profiles were analysed by psychophysiological interaction (PPI toolbox. For the controls and PD patients, the motor areas including the primary motor and premotor areas, supplementary motor area, the cerebellum and parts of the frontal, temporal and parietal gyrus were activated. The right putamen exhibited significant control > PD activation and weaker activity during the bimanual movement relative to the unimanual movement in the control group. The decreased putamen modulation on some nucleus in basal ganglia, such as putamen, thalamus and caudate, and some cortical areas, such as cingulate, parietal, angular, frontal, temporal and occipital gyrus was detected in the bimanual hand movement condition relative to the unimanual movement condition. Between group PPI difference was detected in cingulate gyrus, angular gyrus and precuneus (control > PD and inferior frontal gyrus (PD > control. The deficient putamen activation and its enhanced connectivity with the frontal gyrus could be a correlate of impaired basal ganglia inhibition and frontal gyrus compensation to maintain the task performance during the motor programs of PD patients.
Fujiyama, Hakuei; Van Soom, Jago; Rens, Guy; Cuypers, Koen; Heise, Kirstin-Friederike; Levin, Oron; Swinnen, Stephan P
Even though it has been suggested that the dorsolateral prefrontal cortex (DLPFC) and dorsal premotor cortex (PMd) are highly involved in the planning of bimanual movements, the exact nature (facilitatory or inhibitory) of their role is not well understood. Using a dual-site transcranial magnetic stimulation (TMS) paradigm, we examined the functional influence from DLPFC and PMd to the contralateral primary cortex (M1) during the preparation of a complex bimanual coordination task in which inter-hand movement frequency was manipulated. Only the left PMd showed inter-hand frequency-specific modulations in the interaction with the contralateral M1. Left PMd-right M1 interaction became facilitatory during the preparation phase when the left hand had to move faster than the right hand, while inhibitory modulation was observed when the movement frequency arrangement was reversed. Interestingly, bilateral DLPFC showed a facilitatory interaction with the contralateral M1s during the preparation period only in difficult conditions, irrespective of the inter-hand frequency ratio, suggesting a less task-specific role in the organization of complex bimanual actions. Observed task-related modulations in DLPFC-M1 and left PMd-right M1 interactions during preparation were significantly correlated with up-coming performance, predicting successful bimanual movements. These observations highlight the distinct roles of DLPFC and left PMd in the preparation of bimanual movements that require a differential contribution of each limb. PMID:26963084
Winston D Byblow
Full Text Available Repetitive mirror symmetric bilateral upper limb may be a suitable priming technique for upper limb rehabilitation after stroke. Here we demonstrate neurophysiological and behavioural after-effects in healthy participants after priming with 20 minutes of repetitive active-passive bimanual wrist flexion and extension in a mirror symmetric pattern with respect to the body midline (MIR compared to an control priming condition with alternating flexion-extension (ALT. Transcranial magnetic stimulation (TMS indicated that corticomotor excitability (CME of the passive hemisphere remained elevated compared to baseline for at least 30 minutes after MIR but not ALT, evidenced by an increase in the size of motor evoked potentials in ECR and FCR. Short and long-latency intracortical inhibition (SICI, LICI, short afferent inhibition (SAI and interhemispheric inhibition (IHI were also examined using pairs of stimuli. LICI differed between patterns, with less LICI after MIR compared with ALT, and an effect of pattern on IHI, with reduced IHI in passive FCR 15 minutes after MIR compared with ALT and baseline. There was no effect of pattern on SAI or FCR H-reflex. Similarly, SICI remained unchanged after 20 minutes of MIR. We then had participants complete a timed manual dexterity motor learning task with the passive hand during, immediately after, and 24 hours after MIR or control priming. The rate of task completion was faster with MIR priming compared to control conditions. Finally, ECR and FCR MEPs were examined within a pre-movement facilitation paradigm of wrist extension before and after MIR. ECR, but not FCR, MEPs were consistently facilitated before and after MIR, demonstrating no degradation of selective muscle activation. In summary, mirror symmetric active-passive bimanual movement increases CME and can enhance motor learning without degradation of muscle selectivity. These findings rationalise the use of mirror symmetric bimanual movement as a
We used functional magnetic resonance imagery (fMRI) to study cortical activation during index finger-thumb opposition of both hands using in-phase and out-of-phase modes. In-phase movements activated the sensorimotor cortex. During out-of-phase movements, activations were also observed in the supplementary motor area (SMA), in the cingulate motor area (CMA) and, less frequently, in the anterior cingulate cortex (ACC). As we have previously shown and confirmed in the present study, the same out-of-phase bimanual movements specifically activate the cerebellar second homunculus, leading us to postulate that the cerebellar second homunculus and medial wall motor areas participate in a circuit specifically involved in timing complex movements. (orig.)
Habas, Christophe; Cabanis, Emmanuel Alain [Hopital des Quinze-Vingts, Service de NeuroImagerie, Paris (France)
We used functional magnetic resonance imagery (fMRI) to study cortical activation during index finger-thumb opposition of both hands using in-phase and out-of-phase modes. In-phase movements activated the sensorimotor cortex. During out-of-phase movements, activations were also observed in the supplementary motor area (SMA), in the cingulate motor area (CMA) and, less frequently, in the anterior cingulate cortex (ACC). As we have previously shown and confirmed in the present study, the same out-of-phase bimanual movements specifically activate the cerebellar second homunculus, leading us to postulate that the cerebellar second homunculus and medial wall motor areas participate in a circuit specifically involved in timing complex movements. (orig.)
Hayashi, Takuji; Nozaki, Daichi
When we learn a bimanual motor skill (e.g., rowing a boat), we often break it down into unimanual practices (e.g., a rowing drill with the left or right arm). Such unimanual practice is thought to be useful for learning bimanual motor skills efficiently because the learner can concentrate on learning to perform a simpler component. However, it is not so straightforward to assume that unimanual training (UT) improves bimanual performance. We have previously demonstrated that motor memories for reaching movements consist of three different parts: unimanual-specific, bimanual-specific, and overlapping parts. According to this scheme, UT appears to be less effective, as its training effect is only partially transferred to the same limb for bimanual movement. In the present study, counter-intuitively, we demonstrate that, even after the bimanual skill is almost fully learned by means of bimanual training (BT), additional UT could further improve bimanual skill. We hypothesized that this effect occurs because UT increases the memory content in the overlapping part, which might contribute to an increase in the memory for bimanual movement. To test this hypothesis, we examined whether the UT performed after sufficient BT could improve the bimanual performance. Participants practiced performing bimanual reaching movements (BM) in the presence of a novel force-field imposed only on their left arm. As an index for the motor performance, we used the error-clamp method (i.e., after-effect of the left arm) to evaluate the force output to compensate for the force-field during the reaching movement. After sufficient BT, the training effect reached a plateau. However, UT performed subsequently improved the bimanual performance significantly. In contrast, when the same amount of BT was continued, the bimanual performance remained unchanged, highlighting the beneficial effect of UT on bimanual performance. Considering memory structure, we also expected that BT could improve unimanual
Full Text Available The main purpose was to analyze quantitatively the the average surface EMGs of the muscles that function around the elbow and shoulder joints of both arms in similar bimanual ‘rowing’ movements, which were produced under identical elastic loads applied to the levers (‘oars’. The muscles of PM group (‘pulling’ muscles: elbow flexors, shoulder extensors generated noticeable velocity-dependent dynamic EMG components during the pulling and returning phases of movement and supported a steady-state activity during the hold phase. The muscles of RM group (‘returning’ muscles: elbow extensors, shoulder flexors co-contracted with PM group during the movement phases and decreased activity during the hold phase. The dynamic components of the EMGs strongly depended on the velocity factor in both muscle groups, whereas the side and load factors and combinations of various factors acted only in PM group muscles. Various subjects demonstrated diverse patterns of activity redistribution among muscles. We assume that central commands to the same muscles in two arms may be essentially different during execution of similar movement programs. Extent of the diversity in the EMG patterns of such muscles may reflect the subject’s skilling in motor performance; on the other hand, the diversity can reflect redistribution of activity between synergic muscles, thus providing a mechanism directed against development of the muscle fatigue.
Hudson, Todd E.; Wolfe, Uta; Maloney, Laurence T.
Author Summary In everyday, cluttered environments, moving to reach or grasp an object can result in unintended collisions with other objects along the path of movement. Depending on what we run into (a priceless Ming vase, a crotchety colleague) we can suffer serious monetary or social consequences. It makes sense to choose movement trajectories that trade off the value of reaching a goal against the consequences of unintended collisions along the way. In the research described here, subject...
Hersch, M; Billard, A.
We present a model of human-like reaching movements. This model is then used to give a humanoid robot the ability to imitate human reaching motions. It illustrates that having a robot control similar to human control can greatly ease the human-robot interaction.
Full Text Available Abstract Background Congenital hemiplegia is the most common form of cerebral palsy (CP accounting for 1 in 1300 live births. These children have limitations in capacity to use the impaired upper limb and bimanual coordination deficits which impact on daily activities and participation in home, school and community life. There are currently two diverse intensive therapy approaches. Traditional therapy has adopted a bimanual approach (BIM training and recently, constraint induced movement therapy (CIMT has emerged as a promising unimanual approach. Uncertainty remains about the efficacy of these interventions and characteristics of best responders. This study aims to compare the efficacy of CIMT to BIM training to improve outcomes across the ICF for school children with congenital hemiplegia. Methods/Design A matched pairs randomised comparison design will be used with children matched by age, gender, side of hemiplegia and level of upper limb function. Based on power calculations a sample size of 52 children (26 matched pairs will be recruited. Children will be randomised within pairs to receive either CIMT or BIM training. Both interventions will use an intensive activity based day camp model, with groups receiving the same dosage of intervention delivered in the same environment (total 60 hours over 10 days. A novel circus theme will be used to enhance motivation. Groups will be compared at baseline, then at 3, 26 and 52 weeks following intervention. Severity of congenital hemiplegia will be classified according to brain structure (MRI and white matter fibre tracking, cortical excitability using Transcranial Magnetic Stimulation (TMS, functional use of the hand in everyday tasks (Manual Ability Classification System and Gross Motor Function Classification System (GMFCS. Outcomes will address neurovascular changes (functional MRI, functional connectivity, and brain (reorganisation (TMS, body structure and function (range of motion, spasticity
Modified constraint-induced movement therapy or bimanual occupational therapy following injection of Botulinum toxin-A to improve bimanual performance in young children with hemiplegic cerebral palsy: a randomised controlled trial methods paper
Full Text Available Abstract Background Use of Botulinum toxin-A (BoNT-A for treatment of upper limb spasticity in children with cerebral palsy has become routine clinical practice in many paediatric treatment centres worldwide. There is now high-level evidence that upper limb BoNT-A injection, in combination with occupational therapy, improves outcomes in children with cerebral palsy at both the body function/structure and activity level domains of the International Classification of Functioning, Disability and Health. Investigation is now required to establish what amount and specific type of occupational therapy will further enhance functional outcomes and prolong the beneficial effects of BoNT-A. Methods/Design A randomised, controlled, evaluator blinded, prospective parallel-group trial. Eligible participants were children aged 18 months to 6 years, diagnosed with spastic hemiplegic cerebral palsy and who were able to demonstrate selective motor control of the affected upper limb. Both groups received upper limb injections of BoNT-A. Children were randomised to either the modified constraint-induced movement therapy group (experimental or bimanual occupational therapy group (control. Outcome assessments were undertaken at pre-injection and 1, 3 and 6 months following injection of BoNT-A. The primary outcome measure was the Assisting Hand Assessment. Secondary outcomes included: the Quality of Upper Extremity Skills Test; Pediatric Evaluation of Disability Inventory; Canadian Occupational Performance Measure; Goal Attainment Scaling; Pediatric Motor Activity Log; modified Ashworth Scale and; the modified Tardieu Scale. Discussion The aim of this paper is to describe the methodology of a randomised controlled trial comparing the effects of modified constraint-induced movement therapy (a uni-manual therapy versus bimanual occupational therapy (a bimanual therapy on improving bimanual upper limb performance of children with hemiplegic cerebral palsy following
Janet H Bultitude
Full Text Available It has been suggested that incongruence between signals for motor intention and sensory input can cause pain and other sensory abnormalities. This claim is supported by reports that moving in an environment of induced sensorimotor conflict leads to elevated pain and sensory symptoms in those with certain painful conditions. Similar procedures can lead to reports of anomalous sensations in healthy volunteers too. In the present study, we used mirror visual feedback to investigate the effects of sensorimotor incongruence on responses to stimuli that arise from sources external to the body, in particular, touch. Incongruence between the sensory and motor signals for the right arm was manipulated by having the participants make symmetrical or asymmetrical movements while watching a reflection of their left arm in a parasagittal mirror, or the left hand surface of a similarly positioned opaque board. In contrast to our prediction, sensitivity to the presence of gaps in tactile stimulation of the right forearm was not reduced when participants made asymmetrical movements during mirror visual feedback, as compared to when they made symmetrical or asymmetrical movements with no visual feedback. Instead, sensitivity was reduced when participants made symmetrical movements during mirror visual feedback relative to the other three conditions. We suggest that small discrepancies between sensory and motor information, as they occur during mirror visual feedback with symmetrical movements, can impair tactile processing. In contrast, asymmetrical movements with mirror visual feedback may not impact tactile processing because the larger discrepancies between sensory and motor information may prevent the integration of these sources of information. These results contrast with previous reports of anomalous sensations during exposure to both low and high sensorimotor conflict, but are nevertheless in agreement with a forward model interpretation of perceptual
Levin, Mindy F; Liebermann, Dario G; Parmet, Yisrael; Berman, Sigal
Background The extent to which the upper-limb flexor synergy constrains or compensates for arm motor impairment during reaching is controversial. This synergy can be quantified with a minimal marker set describing movements of the arm-plane. Objectives To determine whether and how (a) upper-limb flexor synergy in patients with chronic stroke contributes to reaching movements to different arm workspace locations and (b) reaching deficits can be characterized by arm-plane motion. Methods Sixteen post-stroke and 8 healthy control subjects made unrestrained reaching movements to targets located in ipsilateral, central, and contralateral arm workspaces. Arm-plane, arm, and trunk motion, and their temporal and spatial linkages were analyzed. Results Individuals with moderate/severe stroke used greater arm-plane movement and compensatory trunk movement compared to those with mild stroke and control subjects. Arm-plane and trunk movements were more temporally coupled in stroke compared with controls. Reaching accuracy was related to different segment and joint combinations for each target and group: arm-plane movement in controls and mild stroke subjects, and trunk and elbow movements in moderate/severe stroke subjects. Arm-plane movement increased with time since stroke and when combined with trunk rotation, discriminated between different subject groups for reaching the central and contralateral targets. Trunk movement and arm-plane angle during target reaches predicted the subject group. Conclusions The upper-limb flexor synergy was used adaptively for reaching accuracy by patients with mild, but not moderate/severe stroke. The flexor synergy, as parameterized by the amount of arm-plane motion, can be used by clinicians to identify levels of motor recovery in patients with stroke. PMID:26510934
Zafer, Hira; Amjad, Imran; Malik, Arshad Nawaz; Shaukat, Enfall
Objective: This study aims at determining the effectiveness of constraint induced movement therapy as compared to bimanual therapy for improving functional status in children with hemiplegic cerebral palsy. Methods: This study was a randomized control trial, children (n = 20) with spastic hemiplegic cerebral palsy was randomly allocated to CIMT (constraint induced movement therapy) and BMT (bimanual therapy) group. The children with spastic hemiplegia, age between 1.5 and 12 year and having 10 degrees of wrist extension and 10 degrees of finger extension were included in study. Treatment regime was two hours of daily training six days a week for two weeks. Constraint was applied to CIMT group for six hours. The outcome tool QUEST was used for baseline and post treatment assessment. Result: CIMT had superior outcome as compared to BMT in improving functional status (p=0.007). On QUEST tool grasp and dissociated movements results were significant (p=0.005) and (p=0.028) respectively. Weight bearing and protective extension resulted in no significant outcome (p=0.080) and (p=0.149) respectively. Dissociated movements and grasp are significantly improved but there is no difference for weight bearing and protective extension in CIMT treated group as compared to BMT treated group. Conclusion: CIMT approach is better in improving functional status of child with cerebral palsy as compared to BMT. Significant improvement in grasp and dissociated movement is noted in group of CIMT while there was no significant improvement in weight bearing and protective extension in CIMT group when compared to BMT. CIMT is considered the appropriate treatment approach for unilateral conditions while BMT for bilateral conditions. PMID:27022371
Hughes, Charmayne M L; Seegelke, Christian; Reissig, Paola
The purpose of the current experiments was to examine whether the problems associated with grasp posture planning during bimanually incongruent movements are due to crosstalk at the motor programming level. Participants performed a grasping and placing task in which they grasped two objects from a table and placed them onto a board to targets that required identical (congruent) or non-identical degrees of rotation (incongruent). The interval between the presentation of the first stimulus and the second stimulus (stimulus onset asynchrony: SOA) was manipulated. Results demonstrate that the problems associated with bimanually incongruent grasp posture planning are reduced at SOA durations longer than 1000ms, indicating that the costs associated with bimanual incongruent movements arise from crosstalk at the motor programming level. In addition, reach-to-grasp times were shorter, and interlimb limb coupling was higher, for congruent, compared to incongruent, object end-orientation conditions in both Experiment 1 and 2. The bimanual interference observed during reach-to-grasp execution is postulated to arise from limitations in the visual motor system or from conceptual language representations. The present results emphasize that bimanual interference arises from constraints active at multiple levels of the neurobiological-cognitive system. PMID:24650762
The Pirate group intervention protocol: description and a case report of a modified constraint-induced movement therapy combined with bimanual training for young children with unilateral spastic cerebral palsy.
Aarts, P.B.M.; Hartingsveldt, M. van; Anderson, P.G.; Tillaar, I. van den; Burg, J. van der; Geurts, A.C.H.
The purpose of this article was to describe a child-friendly modified constraint-induced movement therapy protocol that is combined with goal-directed task-specific bimanual training (mCIMT-BiT). This detailed description elucidates the approach and supports various research reports. This protocol i
Casadio, Maura; Sanguineti, Vittorio; Squeri, Valentina; Masia, Lorenzo; Morasso, Pietro
Skillful manipulation of objects often requires the spatio-temporal coordination of both hands and, at the same time, the compensation of environmental forces. In bimanual coordination, movements of the two hands may be coupled because each hand needs to compensate the forces generated by the other hand or by an object operated by both hands (dynamic coupling), or because the two hands share the same workspace (spatial coupling). We examined how spatial coupling influences bimanual coordination, by looking at the adaptation of velocity-dependent force fields during a task in which the two hands simultaneously perform center-out reaching movements with the same initial position and the same targets, equally spaced on a circle. Subjects were randomly allocated to two groups, which differed in terms of the force fields they were exposed to: in one group (CW-CW), force fields had equal clockwise orientations in both hands; in the other group (CCW-CW), they had opposite orientations. In both groups, in randomly selected trials (catch trials) of the adaptation phase, the force fields were unexpectedly removed. Adaptation was quantified in terms of the changes of directional error for both hand trajectories. Bimanual coordination was quantified in terms of inter-limb longitudinal and sideways displacements, in force field and in catch trials. Experimental results indicate that both arms could simultaneously adapt to the two force fields. However, in the CCW-CW group, adaptation was incomplete for the movements from the central position to the more distant targets with respect to the body. In addition, in this group the left hand systematically leads in the movements toward targets on the left of the starting position, whereas the right hand leads in the movements to targets on the right. We show that these effects are due to a gradual sideways shift of the hands, so that during movements the left hand tends to consistently remain at the left of the right hand. These
Glazebrook, Cheryl M; Welsh, Timothy N; Tremblay, Luc
Presenting target and non-target information in different modalities influences target localization if the non-target is within the spatiotemporal limits of perceptual integration. When using auditory and visual stimuli, the influence of a visual non-target on auditory target localization is greater than the reverse. It is not known, however, whether or how such perceptual effects extend to goal-directed behaviours. To gain insight into how audio-visual stimuli are integrated for motor tasks, the kinematics of reaching movements towards visual or auditory targets with or without a non-target in the other modality were examined. When present, the simultaneously presented non-target could be spatially coincident, to the left, or to the right of the target. Results revealed that auditory non-targets did not influence reaching trajectories towards a visual target, whereas visual non-targets influenced trajectories towards an auditory target. Interestingly, the biases induced by visual non-targets were present early in the trajectory and persisted until movement end. Subsequent experimentation indicated that the magnitude of the biases was equivalent whether participants performed a perceptual or motor task, whereas variability was greater for the motor versus the perceptual tasks. We propose that visually induced trajectory biases were driven by the perceived mislocation of the auditory target, which in turn affected both the movement plan and subsequent control of the movement. Such findings provide further evidence of the dominant role visual information processing plays in encoding spatial locations as well as planning and executing reaching action, even when reaching towards auditory targets. PMID:26253323
Magdoom, K N; Subramanian, D; Chakravarthy, V S; Ravindran, B; Amari, Shun-Ichi; Meenakshisundaram, N
We present a computational model that highlights the role of basal ganglia (BG) in generating simple reaching movements. The model is cast within the reinforcement learning (RL) framework with correspondence between RL components and neuroanatomy as follows: dopamine signal of substantia nigra pars compacta as the temporal difference error, striatum as the substrate for the critic, and the motor cortex as the actor. A key feature of this neurobiological interpretation is our hypothesis that the indirect pathway is the explorer. Chaotic activity, originating from the indirect pathway part of the model, drives the wandering, exploratory movements of the arm. Thus, the direct pathway subserves exploitation, while the indirect pathway subserves exploration. The motor cortex becomes more and more independent of the corrective influence of BG as training progresses. Reaching trajectories show diminishing variability with training. Reaching movements associated with Parkinson's disease (PD) are simulated by reducing dopamine and degrading the complexity of indirect pathway dynamics by switching it from chaotic to periodic behavior. Under the simulated PD conditions, the arm exhibits PD motor symptoms like tremor, bradykinesia and undershooting. The model echoes the notion that PD is a dynamical disease. PMID:21105828
Results suggest that reaching and grasping movements planning and execution might share a common brain network, providing further confirmation to the idea that the neural underpinnings of reaching and grasping may overlap in both spatial and temporal terms (Verhagen et al., 2013.
Bastian, Amy J.
Bimanual coordination is essential for everyday activities. It is thought that different degrees of demands may affect learning of new bimanual patterns. One demand is at the level of performance and involves breaking the tendency to produce mirror-symmetric movements. A second is at a perceptual level and involves controlling each hand to separate (i.e., split) goals. A third demand involves switching between different task contexts (e.g., a different uni- or bimanual task), instead of continuously practicing one task repeatedly. Here, we studied the effect of these task demands on motor planning (reaction time) and execution (error) while subjects learned a novel bimanual isometric pinch force task. In Experiment 1, subjects continuously practiced in one of the two extremes of the following bimanual conditions: (1) symmetric force demands and a perceptually unified target for each hand or (2) asymmetric force demands and perceptually split targets. Subjects performing in the asymmetric condition showed some interference between hands, but all subjects, regardless of group, could learn the isometric pinch force task similarly. In Experiment 2, subjects practiced these and two other conditions, but in a paradigm where practice was briefly interrupted by the performance of either a unimanual or a different bimanual condition. Reaction times were longer and errors were larger well after the interruption when the main movement to be learned required asymmetric forces. There was no effect when the main movement required symmetric forces. These findings demonstrate two main points. First, people can learn bimanual tasks with very different demands on the same timescale if they are not interrupted. Second, interruption during learning can negatively impact both planning and execution and this depends on the demands of the bimanual task to be learned. This information will be important for training patient populations, who may be more susceptible to increased task demands
Gertz, Hanna; Fiehler, Katja
Previous research on reach planning in humans has implicated a frontoparietal network, including the precuneus (PCu), a putative human homolog of the monkey parietal reach region (PRR), and the dorsal premotor cortex (PMd). Using a pro-/anti-reach task, electrophysiological studies in monkeys have demonstrated that the movement goal rather than the location of the visual cue is encoded in PRR and PMd. However, if only the effector but not the movement goal is specified (underspecified conditi...
Kim, Heon-Jeong; Martin, Bernard J
Simulation of human movements is an essential component for proactive ergonomic analysis and biomechanical model development (Chaffin, 2001). Most studies on reach kinematics have described human movements in a static environment, however the models derived from these studies cannot be applied to the analysis of human reach movements in vibratory environments such as in-vehicle operations. This study analyzes three-dimensional joint kinematics of the upper extremity in reach movements performed in static and specific vibratory conditions and investigates vibration transmission to shoulder, elbow, and hand along the body path during pointing tasks. Thirteen seated subjects performed reach movements to five target directions distributed in their right hemisphere. The results show similarities in the characteristics of movement patterns and reach trajectories of upper body segments for static and dynamic environments. In addition, vibration transmission through upper body segments is affected by vibration frequency, direction, and location of the target to be reached. Similarities in the pattern of movement trajectories revealed by filtering vibration-induced oscillations indicate that coordination strategy may not be drastically different in static and vibratory environments. This finding may facilitate the development of active biodynamic models to predict human performance and behavior under whole body vibration exposure. PMID:22814094
Fagard, Jacqueline; Hardy-Leger, Isabelle; Kervella, Claude; Marks, Anne
Studied the effect of interhemispheric communication development on age-related changes in bimanual coordination. Findings indicated that improved interhemispheric communication contributes to progress in bimanual coordination, especially that which requires resisting the attraction of mirror movements in order to rotate both hands with parallel…
Full Text Available The spectral power of intracranial field potentials shows movement-related modulations during reaching movements to different target positions that in frequencies up to the high-γ range (approximately 50 to above 200 Hz can be reliably used for single-trial inference of movement parameters. However, identifying spectral power modulations suitable for single-trial analysis for non-invasive approaches remains a challenge. We recorded non-invasive electroencephalography (EEG during a self-paced center-out and center-in arm movement task, resulting in 8 reaching movement classes (4 center-out, 4 center-in. We found distinct slow (≤ 5 Hz, μ (7.5 to 10 Hz, β (12.5 to 25 Hz, low-γ (27.5 to approximately 50Hz and high-γ (above 50 Hz movement onset- and end-related responses. Movement class-specific spectral power modulations were restricted to the β band at approximately 1 s after movement end and could be explained by the sensitivity of this response to different static, post-movement electromyography (EMG levels. Based on the β band, significant single-trial inference of reaching movement endpoints was possible. The findings of the present study support the idea that single-trial decoding of different reaching movements from non-invasive EEG spectral power modulations is possible, but also suggest that the informative time window is after movement end and that the informative frequency range is restricted to the β band.
Optimal control has been used as a technique to uncover mathematical principles which are observed regularly in the dynamics of human movement. We present two new models of human reaching movements. While both are rooted in optimal control theory, the models were conceived by questioning basic tenets and typical practices used in optimal control as applied to human movement. In the first model, we use cost functions that measure various control signals via the L_infinity norm as opposed to th...
Spivey, M.J.; Dale, R.; Knoblich, G.K.; Grosjean, M.
Spivey, Grosjean, and Knoblich (2005) reported smoothly curved reaching movements, via computer-mouse tracking, which suggested a continuously evolving flow of distributed lexical activation patterns into motor movement during a phonological competitor task. For example, when instructed to click the
Kourtis, Dimitrios; De Saedeleer, Lien; Vingerhoets, Guy
Previous research has shown that handedness consistency might be a more important factor than direction of hand dominance in the performance of various cognitive and motor tasks. We investigated the effect of handedness consistency in bimanual coordination. We employed a task where participants had to respond to visual cues and perform symmetrical or asymmetrical bimanual movements towards cue-designated targets. Response and movement times were recorded in parallel with electroencephalography (EEG). Behavioural analyses showed that participants with inconsistent hand preference were equally fast in initiating symmetrical and asymmetrical bimanual movements, whereas participants with consistent hand preference were slower in initiating (the more demanding) asymmetrical movements. Moreover, the amplitudes of the Movement Related Potential and the suppression of the 10 Hz-mu rhythm were larger in participants with inconsistent hand preference over premotor and primary sensorimotor areas, although it is possible that the suppression of the mu rhythm may also depend on hand dominance. Our findings suggest that individuals with inconsistent hand preference have an advantage in the planning and organization of bimanual movements, which may not be related to the direction of their hand dominance. PMID:24732382
Kudo, Naoki; Choi, Kyuheong; Kagawa, Takahiro; Uno, Yoji
It is well known that planar reaching movements of the human shoulder and elbow joints have invariant features: roughly straight hand paths and bell-shaped velocity profiles. The optimal control models with the criteria of smoothness or precision, which determine a unique movement pattern, predict such features of hand trajectories. In this letter on expanding the research on simple arm reaching movements, we examine whether the smoothness criteria can be applied to whole-body reaching movements with many degrees of freedom. Determining a suitable joint trajectory in the whole-body reaching movement corresponds to the optimization problem with constraints, since body balance must be maintained during a motion task. First, we measured human joint trajectories and ground reaction forces during whole-body reaching movements, and confirmed that subjects formed similar movements with common characteristics in the trajectories of the hand position and body center of mass. Second, we calculated the optimal trajectories according to the criteria of torque and muscle-tension smoothness. While the minimum torque change trajectories were not consistent with the experimental data, the minimum muscle-tension change model was able to predict the stereotyped features of the measured trajectories. To explore the dominant effects of the extension from the torque change to the muscle-tension change, we introduced a weighted torque change cost function. Considering the maximum voluntary contraction (MVC) force of the muscle as the weighting factor of each joint torque, we formulated the weighted torque change cost as a simplified version of the minimum muscle-tension change cost. The trajectories owing to the minimum weighted torque change criterion also showed qualitative agreement with the common features of the measured data. Proper estimation of the MVC forces in the body joints is essential to reproduce human whole-body movements according to the minimum muscle-tension change
Abstract When a visually guided reaching movement is unexpectedly perturbed, it is implicitly corrected in two ways: immediately after the perturbation by feedback control (online correction) and in the next movement by adjusting feedforward motor commands (offline correction or motor adaptation). Although recent studies have revealed a close relationship between feedback and feedforward controls, the nature of this relationship is not yet fully understood. Here, we show that both implicit online and offline movement corrections utilize the same visuomotor map for feedforward movement control that transforms the spatial location of visual objects into appropriate motor commands. First, we artificially distorted the visuomotor map by applying opposite visual rotations to the cursor representing the hand position while human participants reached for two different targets. This procedure implicitly altered the visuomotor map so that changes in the movement direction to the target location were more insensitive or more sensitive. Then, we examined how such visuomotor map distortion influenced online movement correction by suddenly changing the target location. The magnitude of online movement correction was altered according to the shape of the visuomotor map. We also examined offline movement correction; the aftereffect induced by visual rotation in the previous trial was modulated according to the shape of the visuomotor map. These results highlighted the importance of the visuomotor map as a foundation for implicit motor control mechanisms and the intimate relationship between feedforward control, feedback control, and motor adaptation.
Sarlegna, Fabrice R.; Sainburg, Robert L.
While vision and proprioception can both provide information about arm configuration prior to movement, substantial evidence suggests that each modality is used for different stages of the planning process. In this chapter, we provide support for the idea that vision is mainly used to define the trajectory and the kinematics of reaching movements. Proprioception appears to be critical in the transformation of this plan into the motor commands sent to the arm muscles.
Mueller, Stefanie; Fiehler, Katja
Previous studies demonstrated that an effector movement intervening between encoding and reaching to a proprioceptive target determines the underlying reference frame: proprioceptive reach targets are represented in a gaze-independent reference frame if no movement occurs but are represented with respect to gaze after an effector movement (Mueller and Fiehler, 2014a). The present experiment explores whether an effector movement leads to a switch from a gaze-independent, body-centered reference frame to a gaze-dependent reference frame or whether a gaze-dependent reference frame is employed in addition to a gaze-independent, body-centered reference frame. Human participants were asked to reach in complete darkness to an unseen finger (proprioceptive target) of their left target hand indicated by a touch. They completed 2 conditions in which the target hand remained either stationary at the target location (stationary condition) or was actively moved to the target location, received a touch and was moved back before reaching to the target (moved condition). We dissociated the location of the movement vector relative to the body midline and to the gaze direction. Using correlation and regression analyses, we estimated the contribution of each reference frame based on horizontal reach errors in the stationary and moved conditions. Gaze-centered coding was only found in the moved condition, replicating our previous results. Body-centered coding dominated in the stationary condition while body- and gaze-centered coding contributed equally strong in the moved condition. Our results indicate a shift from body-centered to combined body- and gaze-centered coding due to an effector movement before reaching towards proprioceptive targets. PMID:27157885
Lackner, J. R.; Dizio, P.
We evaluated the combined effects on reaching movements of the transient, movement-dependent Coriolis forces and the static centrifugal forces generated in a rotating environment. Specifically, we assessed the effects of comparable Coriolis force perturbations in different static force backgrounds. Two groups of subjects made reaching movements toward a just-extinguished visual target before rotation began, during 10 rpm counterclockwise rotation, and after rotation ceased. One group was seated on the axis of rotation, the other 2.23 m away. The resultant of gravity and centrifugal force on the hand was 1.0 g for the on-center group during 10 rpm rotation, and 1.031 g for the off-center group because of the 0.25 g centrifugal force present. For both groups, rightward Coriolis forces, approximately 0.2 g peak, were generated during voluntary arm movements. The endpoints and paths of the initial per-rotation movements were deviated rightward for both groups by comparable amounts. Within 10 subsequent reaches, the on-center group regained baseline accuracy and straight-line paths; however, even after 40 movements the off-center group had not resumed baseline endpoint accuracy. Mirror-image aftereffects occurred when rotation stopped. These findings demonstrate that manual control is disrupted by transient Coriolis force perturbations and that adaptation can occur even in the absence of visual feedback. An increase, even a small one, in background force level above normal gravity does not affect the size of the reaching errors induced by Coriolis forces nor does it affect the rate of reacquiring straight reaching paths; however, it does hinder restoration of reaching accuracy.
Macaluso, T; Bourdin, C; Buloup, F; Mille, M-L; Sainton, P; Sarlegna, F R; Taillebot, V; Vercher, J-L; Weiss, P; Bringoux, L
Astronauts' training is conventionally performed in a pool to reproduce weightlessness by exploiting buoyancy which is supposed to reduce the impact of gravity on the body. However, this training method has not been scientifically validated yet, and requires first to study the effects of underwater exposure on motor behavior. We examined the influence of neutral buoyancy on kinematic features of whole-body reaching underwater and compared them with those produced on land. Eight professional divers were asked to perform arm reaching movements toward visual targets while standing. Targets were presented either close or far from the subjects (requiring in the latter case an additional whole-body displacement). Reaching movements were performed on land or underwater in two different contexts of buoyancy. The divers either wore a diving suit only with neutral buoyancy applied to their center of mass or were additionally equipped with a submersible simulated space suit with neutral buoyancy applied to their body limbs. Results showed that underwater exposure impacted basic movement features, especially movement speed which was reduced. However, movement kinematics also differed according to the way buoyancy was exerted on the whole-body. When neutral buoyancy was applied to the center of mass only, some focal and postural components of whole-body reaching remained close to land observations, notably when considering the relative deceleration duration of arm elevation and concomitant forward trunk bending when reaching the far target. On the contrary, when neutral buoyancy was exerted on body segments, movement kinematics were close to those reported in weightlessness, as reflected by the arm deceleration phase and the whole-body forward displacement when reaching the far target. These results suggest that astronauts could benefit from the application of neutral buoyancy across the whole-body segments to optimize underwater training and acquire specific motor skills which
Frisoli, Antonio; Procopio, Caterina; Chisari, Carmelo; Creatini, Ilaria; Bonfiglio, Luca; Bergamasco, Massimo; Rossi, Bruno; Carboncini, Maria Chiara
This study, conducted in a group of nine chronic patients with right-side hemiparesis after stroke, investigated the effects of a robotic-assisted rehabilitation training with an upper limb robotic exoskeleton for the restoration of motor function in spatial reaching movements. The robotic assisted rehabilitation training was administered for a period of 6 weeks including reaching and spatial antigravity movements. To assess the carry-over of the observed improvements in movement during training into improved function, a kinesiologic assessment of the effects of the training was performed by means of motion and dynamic electromyographic analysis of reaching movements performed before and after training. The same kinesiologic measurements were performed in a healthy control group of seven volunteers, to determine a benchmark for the experimental observations in the patients' group. Moreover degree of functional impairment at the enrolment and discharge was measured by clinical evaluation with upper limb Fugl-Meyer Assessment scale (FMA, 0-66 points), Modified Ashworth scale (MA, 0-60 pts) and active ranges of motion. The robot aided training induced, independently by time of stroke, statistical significant improvements of kinesiologic (movement time, smoothness of motion) and clinical (4.6 ± 4.2 increase in FMA, 3.2 ± 2.1 decrease in MA) parameters, as a result of the increased active ranges of motion and improved co-contraction index for shoulder extension/flexion. Kinesiologic parameters correlated significantly with clinical assessment values, and their changes after the training were affected by the direction of motion (inward vs. outward movement) and position of target to be reached (ipsilateral, central and contralateral peripersonal space). These changes can be explained as a result of the motor recovery induced by the robotic training, in terms of regained ability to execute single joint movements and of improved interjoint coordination of elbow
Full Text Available Abstract This study, conducted in a group of nine chronic patients with right-side hemiparesis after stroke, investigated the effects of a robotic-assisted rehabilitation training with an upper limb robotic exoskeleton for the restoration of motor function in spatial reaching movements. The robotic assisted rehabilitation training was administered for a period of 6 weeks including reaching and spatial antigravity movements. To assess the carry-over of the observed improvements in movement during training into improved function, a kinesiologic assessment of the effects of the training was performed by means of motion and dynamic electromyographic analysis of reaching movements performed before and after training. The same kinesiologic measurements were performed in a healthy control group of seven volunteers, to determine a benchmark for the experimental observations in the patients’ group. Moreover degree of functional impairment at the enrolment and discharge was measured by clinical evaluation with upper limb Fugl-Meyer Assessment scale (FMA, 0–66 points, Modified Ashworth scale (MA, 0–60 pts and active ranges of motion. The robot aided training induced, independently by time of stroke, statistical significant improvements of kinesiologic (movement time, smoothness of motion and clinical (4.6 ± 4.2 increase in FMA, 3.2 ± 2.1 decrease in MA parameters, as a result of the increased active ranges of motion and improved co-contraction index for shoulder extension/flexion. Kinesiologic parameters correlated significantly with clinical assessment values, and their changes after the training were affected by the direction of motion (inward vs. outward movement and position of target to be reached (ipsilateral, central and contralateral peripersonal space. These changes can be explained as a result of the motor recovery induced by the robotic training, in terms of regained ability to execute single joint movements and of improved
Williams, Joshua L; Corbetta, Daniela
Prior research on infant reaching has shown that providing infants with repeated opportunities to reach for objects aids the emergence and progression of reaching behavior. This study investigated the effect of movement consequences on the process of learning to reach in pre-reaching infants. Thirty-five infants aged 2.9 months at the onset of the study were randomly assigned to 1 of 3 groups. Two groups received a 14-day intervention to distinct reaching tasks: (1) in a contingent group, a toy target moved and sounded upon contact only, and (2) in a continuous group, the toy moved and sounded continuously, independent of hand-toy contact. A third control group did not receive any intervention; this group's performance was assessed only on 2 days at a 15-day interval. Results revealed that infants in the contingent group made the most progress over time compared to the two other groups. Infants in this group made significantly more overall contacts with the sounding/moving toy, and they increased their rate of visually attended target contacts relative to non-visually attended target contacts compared to the continuous and control groups. Infants in the continuous group did not differ from the control group on the number of hand-toy contacts nor did they show a change in visually attended target versus non-visually attended target contacts ratio over time. However, they did show an increase in movement speed, presumably in an attempt to attain the moving toy. These findings highlight the importance of contingent movement consequences as a critical reinforcer for the selection of action and motor learning in early development. Through repeated opportunities to explore movement consequences, infants discover and select movements that are most successful to the task-at-hand. This study further demonstrates that distinct sensory-motor experiences can have a significant impact on developmental trajectories and can influence the skills young infants will discover through
Reichenbach, Alexandra; Thielscher, Axel; Peer, Angelika;
neuroimaging studies have focused mainly on identifying the parts of the posterior parietal cortex (PPC) that contribute to visually guided movements. We used event-related TMS and force perturbations of the reaching hand to test whether the same sub-regions of the left PPC contribute to the processing of...... proprioceptive-only and of multi-sensory information about hand position when reaching for a visual target. TMS over two distinct stimulation sites elicited differential effects: TMS applied over the posterior part of the medial intraparietal sulcus (mIPS) compromised reaching accuracy when proprioception was...... the only sensory information available for correcting the reaching error. When visual feedback of the hand was available, TMS over the anterior intraparietal sulcus (aIPS) prolonged reaching time. Our results show for the first time the causal involvement of the posterior mIPS in processing...
Sartori, Luisa; Camperio-Ciani, Andrea; Bulgheroni, Maria; Castiello, Umberto
Humans show a spontaneous tendency to increase the velocity of their movements depending on the linear extent of their trajectory in order to keep execution time approximately constant. Termed the isochrony principle, this compensatory mechanism refers to the observation that the velocity of voluntary movements increases proportionally with their linear extension. Although there is a wealth of psychophysical data regarding isochrony in humans, there is none regarding non-human primates. The present study attempts to fill that gap by investigating reach-to-grasp movement kinematics in free-ranging macaques. Video footage of monkeys grasping objects located at different distances was analyzed frame-by-frame using digitalization techniques. The amplitude of arm peak velocity was found to be correlated with the distance to be covered, and total movement duration remained invariant although target distances varied. Like in humans, the "isochrony principle" seems to be operative as there is a gearing down/up of movement velocity that is proportional to the distance to be covered in order to allow for a relatively constant movement duration. Based on a centrally generated temporal template, this mode of motor programming could be functional in macaques given the high speed and great instability of posture and joint kinematics characterizing their actions. The data presented here take research in the field of comparative motor control a step forward as they are based on precise measurements of spontaneous grasping movements by animals living/acting in their natural environment. PMID:23658547
Bevans, Allen Leon
This thesis presents the results of an exploratory comparative study investigating the potential effects of bimanual interaction on creativity. Recent research from cognitive psychology and neuroscience suggests that body movement influences divergent thinking performance in previously unexpected ways. Divergent thinking is the process of generating multiple valid responses to a situation, and is an important part of creative behaviour. To examine the impact of the body movements afforded by ...
Joshua L Williams
Full Text Available Prior research on infant reaching has shown that providing infants with repeated opportunities to reach for objects aids the emergence and progression of reaching behavior. This study investigated the effect of movement consequences on the process of learning to reach in pre-reaching infants. Thirty-five infants aged 2.9 months at the onset of the study were randomly assigned to 1 of 3 groups. Two groups received a 14-day intervention to distinct reaching tasks: (1 in a contingent group, a toy target moved and sounded upon contact only, and (2 in a continuous group, the toy moved and sounded continuously, independent of hand-toy contact. A third control group did not receive any intervention; this group’s performance was assessed only on two days at a 15-day interval. Results revealed that infants in the contingent group made the most progress over time compared to the two other groups. Infants in this group made significantly more overall contacts with the sounding/moving toy, and they increased their rate of visually-attended target contacts relative to non-visually-attended target contacts compared to the continuous and control groups. Infants in the continuous group did not differ from the control group on the number of hand-toy contacts nor did they show a change in visually-attended target versus non-visually-attended target contacts ratio over time. However, they did show an increase in movement speed, presumably in an attempt to attain the moving toy. These findings highlight the importance of contingent movement consequences as a critical reinforcer for the selection of action and motor learning in early development. Through repeated opportunities to explore movement consequences, infants discover and select movements that are most successful to the task-at-hand. This study further demonstrates that distinct sensory-motor experiences can have a significant impact on developmental trajectories and can influence the skills young infants
Maslovat, Dana; Lam, Melanie Y; Brunke, Kirstin M; Chua, Romeo; Franks, Ian M
Anchoring in cyclical movements has been defined as regions of reduced spatial or temporal variability [Beek, P. J. (1989). Juggling dynamics. PhD thesis. Amsterdam: Free University Press] that are typically found at movement reversal points. For in-phase and anti-phase movements, synchronizing reversal points with a metronome pulse has resulted in decreased anchor point variability and increased pattern stability [Byblow, W. D., Carson, R. G., & Goodman, D. (1994). Expressions of asymmetries and anchoring in bimanual coordination. Human Movement Science, 13, 3-28; Fink, P. W., Foo, P., Jirsa, V. K., & Kelso, J. A. S. (2000). Local and global stabilization of coordination by sensory information. Experimental Brain Research, 134, 9-20]. The present experiment examined anchoring during acquisition, retention, and transfer of a 90 degrees phase-offset continuous bimanual coordination pattern (whereby the right limb lags the left limb by one quarter cycle), involving horizontal flexion about the elbow. Three metronome synchronization strategies were imposed: participants either synchronized maximal flexion of the right arm (i.e., single metronome), both flexion and extension of the right arm (i.e., double metronome within-limb), or flexion of each arm (i.e., double metronome between-limb) to an auditory metronome. In contrast to simpler in-phase and anti-phase movements, synchronization of additional reversal points to the metronome did not reduce reversal point variability or increase pattern stability. Furthermore, practicing under different metronome synchronization strategies did not appear to have a significant effect on the rate of acquisition of the pattern. PMID:18842313
Bundy, David T.; Pahwa, Mrinal; Szrama, Nicholas; Leuthardt, Eric C.
Objective. Electrocorticography (ECoG) signals have emerged as a potential control signal for brain-computer interface (BCI) applications due to balancing signal quality and implant invasiveness. While there have been numerous demonstrations in which ECoG signals were used to decode motor movements and to develop BCI systems, the extent of information that can be decoded has been uncertain. Therefore, we sought to determine if ECoG signals could be used to decode kinematics (speed, velocity, and position) of arm movements in 3D space. Approach. To investigate this, we designed a 3D center-out reaching task that was performed by five epileptic patients undergoing temporary placement of ECoG arrays. We used the ECoG signals within a hierarchical partial-least squares (PLS) regression model to perform offline prediction of hand speed, velocity, and position. Main Results. The hierarchical PLS regression model enabled us to predict hand speed, velocity, and position during 3D reaching movements from held-out test sets with accuracies above chance in each patient with mean correlation coefficients between 0.31 and 0.80 for speed, 0.27 and 0.54 for velocity, and 0.22 and 0.57 for position. While beta band power changes were the most significant features within the model used to classify movement and rest, the local motor potential and high gamma band power changes, were the most important features in the prediction of kinematic parameters. Significance. We believe that this study represents the first demonstration that truly three-dimensional movements can be predicted from ECoG recordings in human patients. Furthermore, this prediction underscores the potential to develop BCI systems with multiple degrees of freedom in human patients using ECoG.
DiZio, P.; Lackner, J. R.
When reaching movements are made during passive constant velocity body rotation, inertial Coriolis accelerations are generated that displace both movement paths and endpoints in their direction. These findings directly contradict equilibrium point theories of movement control. However, it has been argued that these movement errors relate to subjects sensing their body rotation through continuing vestibular activity and making corrective movements. In the present study, we evaluated the reaching movements of five labyrinthine-defective subjects (lacking both semicircular canal and otolith function) who cannot sense passive body rotation in the dark and five age-matched, normal control subjects. Each pointed 40 times in complete darkness to the location of a just extinguished visual target before, during, and after constant velocity rotation at 10 rpm in the center of a fully enclosed slow rotation room. All subjects, including the normal controls, always felt completely stationary when making their movements. During rotation, both groups initially showed large deviations of their movement paths and endpoints in the direction of the transient Coriolis forces generated by their movements. With additional per-rotation movements, both groups showed complete adaptation of movement curvature (restoration of straight-line reaches) during rotation. The labyrinthine-defective subjects, however, failed to regain fully accurate movement endpoints after 40 reaches, unlike the control subjects who did so within 11 reaches. Postrotation, both groups' movements initially had mirror image curvatures to their initial per-rotation reaches; the endpoint aftereffects were significantly different from prerotation baseline for the control subjects but not for the labyrinthine-defective subjects reflecting the smaller amount of endpoint adaptation they achieved during rotation. The labyrinthine-defective subjects' movements had significantly lower peak velocity, higher peak elevation
Popović Mirjana B.
Full Text Available This paper presents control methods for restoration of reaching and grasping that mimics the mapping in the space of output states found in healthy subjects. The hypothesis was that the externally driven movements are most likely to advance the recovery of functioning if they follow lifelike control mechanisms. For this, it is important to analyze movement considering the conditions such as: 1 variety of functional tasks (drinking, writing, using computer disk; 2 different locations of the object (with respect to the body; with respect to the active arm; 3 variable loading of the hand (light, heavy; and 4 available grasp strategy (palmar, lateral, pinch. The overall goals of our study were the following 1 identification of coordinated synergies in functional tasks, 2 investigation of differences and similarities between these synergies related to different grasp types, and 3 analysis of the impact of direction, distance and load to synergies. Three spatial reaching synergies were validated for the following coordinated rotations: shoulder adduction/abduction vs. elbow flexion/extension angular velocity (synergy SI, humeral rotation vs. elbow flexion/extension angular velocity (synergy S2, and shoulder vs. elbow flexion/extension angular velocity (synergy S3. These are timely synchronized with the phases of functional tasks; where four reaching phases were distinguished. Here, we present alternation of synergies' coupling during successive phases of a functional task. Preliminary results indicate that the two phases of a functional task termed "no-object" phases used one coupling, between synergies S2 and S3; while the two other phases termed "object" phases were coupled by synergies SI and S2. We established the generalization on the following two objectives: the discrimination of tasks' phases and matching the synergies with task phases. This result reduces the number of mappings necessary for the design of neuroprosthesis with life
Mariana Martins dos Santos
Full Text Available OBJETIVOS: verificar a influência das propriedades dos objetos nos ajustes realizados por lactentes típicos e com Síndrome de Down (SD dos quatro aos oito meses de idade ao alcançar e apreender objetos. MÉTODOS: 16 lactentes, avaliados uma vez ao mês dos 4 aos 8 meses, sendo oito típicos e oito com SD. Quatro objetos esféricos (maleável grande, maleável pequeno, rígido grande e rígido pequeno foram apresentados, e os cinco primeiros movimentos válidos foram registrados para análise das variáveis: ajuste proximal (uni e bimanual, ajuste distal (orientação da palma, abertura da mão e apreensão do objeto. RESULTADOS: os lactentes típicos apresentaram mais ajuste bimanual para objetos grandes aos seis e oito meses e os com SD aos sete meses. Quanto aos ajustes distais, os lactentes típicos variaram seu comportamento enquanto os com SD apresentaram uso predominante da posição oblíqua. Em geral, o grupo típico apresentou maior sucesso na apreensão dos objetos rígidos e maleável pequeno quando comparados aos lactentes com SD. CONCLUSÕES: Os lactentes com SD apresentaram menor variedade de ajustes o que levou a um menor sucesso na apreensão, possivelmente devido a restrições intrínsecas da SD.OBJECTIVES: to verify the influence that properties of objects have on the reaching and grasping adjustments made by infants with and without Down syndrome (DS between four to eight months of age. METHODS: 16 infants, eight typical and eight with DS, were evaluated once a month from months 4 to 8. Four spherical objects (large soft, small soft, large hard and small hard were offered and the first five valid movements were recorded for analysis of the variables: proximal adjustment (uni- and bimanual, distal adjustments (palm orientation, hand opening and grasping of the object. RESULTS: the typical infants displayed greater bimanual adjustment for large objects at six and eight months and those with DS at seven months. As for distal
Rymer W Zev
Full Text Available Abstract Background and purpose Providing active assistance to complete desired arm movements is a common technique in upper extremity rehabilitation after stroke. Such active assistance may improve recovery by affecting somatosensory input, motor planning, spasticity or soft tissue properties, but it is labor intensive and has not been validated in controlled trials. The purpose of this study was to investigate the effects of robotically administered active-assistive exercise and compare those with free reaching voluntary exercise in improving arm movement ability after chronic stroke. Methods Nineteen individuals at least one year post-stroke were randomized into one of two groups. One group performed 24 sessions of active-assistive reaching exercise with a simple robotic device, while a second group performed a task-matched amount of unassisted reaching. The main outcome measures were range and speed of supported arm movement, range, straightness and smoothness of unsupported reaching, and the Rancho Los Amigos Functional Test of Upper Extremity Function. Results and discussion There were significant improvements with training for range of motion and velocity of supported reaching, straightness of unsupported reaching, and functional movement ability. These improvements were not significantly different between the two training groups. The group that performed unassisted reaching exercise improved the smoothness of their reaching movements more than the robot-assisted group. Conclusion Improvements with both forms of exercise confirmed that repeated, task-related voluntary activation of the damaged motor system is a key stimulus to motor recovery following chronic stroke. Robotically assisting in reaching successfully improved arm movement ability, although it did not provide any detectable, additional value beyond the movement practice that occurred concurrently with it. The inability to detect any additional value of robot-assisted reaching
Dizio, P.; Lackner, J. R.
1. Reaching movements made in a rotating room generate Coriolis forces that are directly proportional to the cross product of the room's angular velocity and the arm's linear velocity. Such Coriolis forces are inertial forces not involving mechanical contact with the arm. 2. We measured the trajectories of arm movements made in darkness to a visual target that was extinguished at the onset of each reach. Prerotation subjects pointed with both the right and left arms in alternating sets of eight movements. During rotation at 10 rpm, the subjects reached only with the right arm. Postrotation, the subjects pointed with the left and right arms, starting with the left, in alternating sets of eight movements. 3. The initial perrotary reaching movements of the right arm were highly deviated both in movement path and endpoint relative to the prerotation reaches of the right arm. With additional movements, subjects rapidly regained straight movement paths and accurate endpoints despite the absence of visual or tactile feedback about reaching accuracy. The initial postrotation reaches of the left arm followed straight paths to the wrong endpoint. The initial postrotation reaches of the right arm had paths with mirror image curvature to the initial perrotation reaches of the right arm but went to the correct endpoint. 4. These observations are inconsistent with current equilibrium point models of movement control. Such theories predict accurate reaches under our experimental conditions. Our observations further show independent implementation of movement and posture, as evidenced by transfer of endpoint adaptation to the nonexposed arm without transfer of path adaptation. Endpoint control may occur at a relatively central stage that represents general constraints such as gravitoinertial force background or egocentric direction relative to both arms, and control of path may occur at a more peripheral stage that represents moments of inertia and muscle dynamics unique to each
Pigeon, Pascale; Bortolami, Simone B.; DiZio, Paul; Lackner, James R.
When reaching movements involve simultaneous trunk rotation, additional interaction torques are generated on the arm that are absent when the trunk is stable. To explore whether the CNS compensates for such self-generated interaction torques, we recorded hand trajectories in reaching tasks involving various amplitudes and velocities of arm extension and trunk rotation. Subjects pointed to three targets on a surface slightly above waist level. Two of the target locations were chosen so that a similar arm configuration relative to the trunk would be required for reaching to them, one of these targets requiring substantial trunk rotation, the other very little. Significant trunk rotation was necessary to reach the third target, but the arm's radial distance to the body remained virtually unchanged. Subjects reached at two speeds-a natural pace (slow) and rapidly (fast)-under normal lighting and in total darkness. Trunk angular velocity and finger velocity relative to the trunk were higher in the fast conditions but were not affected by the presence or absence of vision. Peak trunk velocity increased with increasing trunk rotation up to a maximum of 200 degrees /s. In slow movements, peak finger velocity relative to the trunk was smaller when trunk rotation was necessary to reach the targets. In fast movements, peak finger velocity was approximately 1.7 m/s for all targets. Finger trajectories were more curved when reaching movements involved substantial trunk rotation; however, the terminal errors and the maximal deviation of the trajectory from a straight line were comparable in slow and fast movements. This pattern indicates that the larger Coriolis, centripetal, and inertial interaction torques generated during rapid reaches were compensated by additional joint torques. Trajectory characteristics did not vary with the presence or absence of vision, indicating that visual feedback was unnecessary for anticipatory compensations. In all reaches involving trunk
Chen, Chun-Fu; Huang, Kuo-Chen
This study investigated the effects of target distance (30, 35, and 40 cm) and the color of background lighting (red, green, blue, and yellow) on the duration of movements made by participants with low vision, myopia, and normal vision while performing a reaching task; 48 students (21 women, 27 men; M age = 21.8 year, SD = 2.4) participated in the study. Participants reached for a target (a white LED light) whose vertical position varied randomly across trials, ranging in distance from 30 to 40 cm. Movement time was analyzed using a 3 (participant group) × [4 (color of background lighting) × 3 (movement distance)] mixed-design ANOVA model. Results indicated longer times for completing a reaching movement when: participants belonged to the low vision group; the target distance between the starting position and the target position was longer (40 cm); and the reaching movement occurred in the red-background lighting condition. These results are particularly relevant for situations in which a user is required to respond to a signal by reaching toward a button or an icon. PMID:27166331
Scharoun, Sara M.; Scanlan, Kelly A.; Bryden, Pamela J.
As numerous movement options are available in reaching and grasping, of particular interest are what factors influence an individual’s choice of action. In the current study a preferential reaching task was used to assess the propensity for right handers to select their preferred hand and grasp a coffee mug by the handle in both independent and joint action object manipulation contexts. Mug location (right-space, midline, and left-space) and handle orientation (toward, away, to left, and to right of the participant) varied in four tasks that differed as a function of intention: (1) pick-up (unimanual, independent); (2) pick-up and pour (bimanual, independent); (3) pick-up and pass (unimanual, joint action); and (4) pick-up, pour and pass (bimanual, joint action). In line with previous reports, a right-hand preference for unimanual tasks was observed. Furthermore, extending existing literature to a preferential reaching task, role differentiation between the hands in bimanual tasks (i.e., preferred hand mobilizing, non-preferred hand stabilizing) was displayed. Finally, right-hand selection was greatest in right space, albeit lower in bimanual tasks compared to what is typically reported in unimanual tasks. Findings are attributed to the desire to maximize biomechanical efficiency in reaching. Grasp postures were also observed to reflect consideration of efficiency. More specifically, within independent object manipulation (pick-up; pick-up and pour) participants only grasped the mug by the handle when it afforded a comfortable posture. Furthermore, in joint action (pick-up and pass; pick-up, pour and pass), the confederate was only offered the handle if the intended action of the confederate was similar or required less effort than that of the participant. Together, findings from the current study add to our knowledge of hand and grasp selection in unimanual and bimanual object manipulation, within the context of both independent and joint action tasks. PMID
Feldman Anatol G
Full Text Available Abstract Background Virtual reality (VR is an innovative tool for sensorimotor rehabilitation increasingly being employed in clinical and community settings. Despite the growing interest in VR, few studies have determined the validity of movements made in VR environments with respect to real physical environments. The goal of this study was to compare movements done in physical and virtual environments in adults with motor deficits to those in healthy individuals. Methods The participants were 8 healthy adults and 7 adults with mild left hemiparesis due to stroke. Kinematics of functional arm movements involving reaching, grasping and releasing made in physical and virtual environments were analyzed in two phases: 1 reaching and grasping the ball and 2 ball transport and release. The virtual environment included interaction with an object on a 2D computer screen and haptic force feedback from a virtual ball. Temporal and spatial parameters of reaching and grasping were determined for each phase. Results Individuals in both groups were able to reach, grasp, transport, place and release the virtual and real ball using similar movement strategies. In healthy subjects, reaching and grasping movements in both environments were similar but these subjects used less wrist extension and more elbow extension to place the ball on the virtual vertical surface. Participants with hemiparesis made slower movements in both environments compared to healthy subjects and during transport and placing of the ball, trajectories were more curved and interjoint coordination was altered. Despite these differences, patients with hemiparesis also tended to use less wrist extension during the whole movement and more elbow extension at the end of the placing phase. Conclusion Differences in movements made by healthy subjects in the two environments may be explained by the use of a 2D instead of a 3D virtual environment and the absence of haptic feedback from the VR target
Hilt, P. M.; Berret, B.; Papaxanthis, C.; Stapley, P. J.; Pozzo, T.
When moving, humans must overcome intrinsic (body centered) and extrinsic (target-related) redundancy, requiring decisions when selecting one motor solution among several potential ones. During classical reaching studies the position of a salient target determines where the participant should reach, constraining the associated motor decisions. We aimed at investigating implicit variables guiding action selection when faced with the complexity of human-environment interaction. Subjects had to perform whole body reaching movements towards a uniform surface. We observed little variation in the self-chosen motor strategy across repeated trials while movements were variable across subjects being on a continuum from a pure ‘knee flexion’ associated with a downward center of mass (CoM) displacement to an ‘ankle dorsi-flexion’ associated with an upward CoM displacement. Two optimality criteria replicated these two strategies: a mix between mechanical energy expenditure and joint smoothness and a minimization of the amount of torques. Our results illustrate the presence of idiosyncratic values guiding posture and movement coordination that can be combined in a flexible manner as a function of context and subject. A first value accounts for the reach efficiency of the movement at the price of selecting possibly unstable postures. The other predicts stable dynamic equilibrium but requires larger energy expenditure and jerk. PMID:27053508
Kasuga, Shoko; Nozaki, Daichi
When a neural movement controller, called an "internal model," is adapted to a novel environment, the movement error needs to be appropriately associated with the controller. However, their association is not necessarily guaranteed for bimanual movements in which two controllers--one for each hand--result in two movement errors. Considering the implicit nature of the adaptation process, the movement error of one hand can be erroneously associated with the controller of the other hand. Here, we investigated this credit-assignment problem in bimanual movement by having participants perform bimanual, symmetric back-and-forth movements while displaying the position of the right hand only with a cursor. In the training session, the cursor position was gradually rotated clockwise, such that the participants were unaware of the rotation. The movement of the right hand gradually rotated counterclockwise as a consequence of adaptation. Although the participants knew that the cursor reflected the movement of the right hand, such gradual adaptation was also observed for the invisible left hand, especially when the cursor was presented on the left side of the display. Thus the movement error of the right hand was implicitly assigned to the left-hand controller. Such cross talk in credit assignment might influence motor adaptation performance, even when two cursors are presented; the adaptation was impaired when the rotations imposed on the cursors were opposite compared with when they were in the same direction. These results indicate the inherent presence of cross talk in the process of associating action with consequence in bimanual movement. PMID:21653713
Julià L Amengual
Full Text Available The study of the movement related brain potentials (MRPBs needs accurate technical approaches to disentangle the specific patterns of bran activity during the preparation and execution of movements. During the last forty years, synchronizing the electromiographic activation (EMG of the muscle with the electrophysiological recordings (EEG has been commonly ussed for these purposes. However, new clinical approaches in the study of motor diseases and rehabilitation suggest the demand of new paradigms that might go further into the study of the brain activity associated with the kinematics of movement. As a response to this call, we have used a 3-D hand tracking system with the aim to record continuously the position of an ultrasonic sender located on the hand during the performance of multi-joint self-pace movements. We synchronized the time-series of position of velocity of the sender with the EEG recordings, obtaining specific patterns of brain activity as a function of the fluctuations of the kinematics during the natural movement performance. Additionally, the distribution of the brain activity during the preparation and execution phases of movement was similar that reported previously using the EMG, suggesting the validity of our technique. We claim that this paradigm could be usable in patients because of its simplicity and the potential knowledge that can be extracted from clinical protocols.
Hagan, Maureen A.; Dean, Heather L.; Pesaran, Bijan
The posterior parietal cortex is situated between visual and motor areas and supports coordinated visually guided behavior. Area LIP in the intraparietal sulcus contains representations of visual space and has been extensively studied in the context of saccades. However, area LIP has not been studied during coordinated movements, so it is not known whether saccadic representations in area LIP are influenced by coordinated behavior. Here, we studied spiking and local field potential (LFP) acti...
Gray Jamieson, Gwendolyn
The women’s health movement shocked and scandalised when it burst into Australian politics in the early 1970s. It cast the light of day onto taboo subjects such as sexual assault, abortion and domestic violence, provoking outrage and condemnation. Some of the services women created for themselves were subjected to police raids; sex education material was branded ‘indecent’. Moreover, women dared to criticise revered institutions, such as the medical system. Yet for all its perceived radicalis...
Alaverdashvili, Mariam; Leblond, Hugues; Rossignol, Serge; Whishaw, Ian Q
The forelimb movements (skilled reaching) used by rats to reach for a single food pellet to place into the mouth have been used to model many neurological conditions. They have been described as a sequence of oppositions of head-pellet, paw-pellet and pellet-mouth that can be described as movements of the distal portion of body segments in relation to their fixed proximal joints. Movement scoring is difficult, however, because the location and movement of body segments is estimated through the overlying fur and skin, which is pliable and partially obscures movement. Using moderately high-speed cineradiographic filming from lateral, dorsal, and frontal perspectives, the present study describes how forelimb and skeletal bones move during the skilled reaching act. The analysis indicates that: (i) head movements for orienting to food, enabled by the vertical orientation of the rostral spinal cord, are mainly independent of trunk movement, (ii) skilled reaching consists of a sequence of upper arm and extremity movements each involving a number of concurrent limb segment and joint movements and (iii) food pellets are retrieved from the paw using either the incisors and/or tongue. The findings are discussed in relation to the idea that X-ray cinematography is valuable tool for assisting descriptive analysis and can contribute to understanding general principles of the relations between whole body, head, oral, and upper extremity movement. PMID:18514337
The fronto-parietal reach network in primates comprises the dorsal premotor cortex (PMd) and the parietal reach region (PRR). The spiking activity of neurons in these areas is typically highly selective for the direction of a planned reach movement. For a large-enough population of motor-tuned neurons, the preferred movement direction (PD: direction of highest firing rate) of the individual neurons cover the full range of possible directions . An important consequence of this heterogenity ...
Lafe, Charley W; Pacheco, Matheus M; Newell, Karl M
Visual information plays an adaptive role in the relation between bimanual force coupling and error corrective processes of isometric force control. In the present study, the evolving distribution of the relative phase properties of bimanual isometric force coupling was examined by scaling within a trial the temporal feedback rate of visual intermittency (short to long presentation intervals and vice versa). The force error (RMSE) was reduced, and time-dependent irregularity (SampEn) of the force output was increased with greater amounts of visual information (shorter intermittency). Multi-stable coordination patterns of bimanual isometric force control were differentially shifted toward and away from the intrinsic dynamics by the changing the intermittency of visual information. The distribution of Hilbert transformed relative phase values showed progressively a predominantly anti-phase mode under less intermittent visual information to predominantly an in-phase mode with limited (almost no) visual information. Correlation between the hands showed a continuous reduction, rather than abrupt "transition," with increase in visual information, although no mean negative correlation was realized, despite the tendency towards an anti-phase distribution. Lastly, changes in both the performance outcome and bimanual isometric force coordination occurred at visual feedback rates faster than the minimal visual processing times established from single limb movement and isometric force protocols. PMID:27017544
Shirzad, Navid; Van der Loos, H F Machiel
The notion of an optimal difficulty during practice has been articulated in many areas of cognitive psychology: flow theory, the challenge point framework, and desirable difficulties. Delivering exercises at a participant's desired difficulty has the potential to improve both motor learning and users' engagement in therapy. Motivation and engagement are among the contributing factors to the success of exercise programs. The authors previously demonstrated that error amplification can be used to introduce levels of challenge into a robotic reaching task, and that machine-learning algorithms can dynamically adjust difficulty to the desired level with 85% accuracy. Building on these findings, we present the results of a proof-of-concept study investigating the impacts of practicing under desirable difficulty conditions. A control condition with a predefined random order for difficulty levels was deemed more suitable for this study (compared to constant or continuously increasing difficulty). By practicing the task at their desirable difficulties, participants in the experimental group perceived their performance at a significantly higher level and reported lower required effort to complete the task, in comparison to a control group. Moreover, based on self-reports, participants in the experimental group were willing, on average, to continue the training session for 4.6 more training blocks (∼45 min) compared to the control group's average. This study demonstrates the efficiency of delivering the exercises at the user's desired difficulty level to improve the user's engagement in exercise tasks. Future work will focus on clinical feasibility of this approach in increasing stroke survivors' engagement in their therapy programs. PMID:25945816
Danion, Frederic; Jirsa, Viktor K.
Predicting the consequences of actions is fundamental for skilled motor behavior. We investigated whether motor prediction is influenced by the fact that some movements are easier to perform and stabilize than others. Twelve subjects performed a bimanual rhythmical task either symmetrically or asymmetrically (the latter being more difficult and…
Shockley, Kevin; Turvey, Michael T.
In 2 experiments, bimanual 1:1 rhythmic coordination was performed concurrently with encoding or retrieval of word lists. Effects of divided attention (DA) on coordination were indexed by changes in mean relative phase and recurrence measures of shared activity between the 2 limbs. Effects of DA on memory were indexed by deficits in recall…
Full Text Available When humans move simultaneously both hands strong coupling effects arise and neither of the two hands is able to perform independent actions. It has been suggested that such motor constraints are tightly linked to action representation rather than to movement execution. Hence, bimanual tasks can represent an ideal experimental tool to investigate internal motor representations in those neurological conditions in which the movement of one hand is impaired. Indeed, any effect on the ‘moving’ (healthy hand would be caused by the constraints imposed by the ongoing motor program of the ‘impaired’ hand. Here, we review recent studies that successfully utilized the above-mentioned paradigms to investigate some types of productive motor behaviors in stroke patients. Specifically, bimanual tasks have been employed in left hemiplegic patients who report illusory movements of their contralesional limbs (anosognosia for hemiplegia. They have also been administered to patients affected by a specific monothematic delusion of body ownership, namely the belief that another person’s arm and his/her voluntary action belong to them. In summary, the reviewed studies show that bimanual tasks are a simple and valuable experimental method apt to reveal information about the motor programs of a paralyzed limb. Therefore, it can be used to objectively examine the cognitive processes underpinning motor programming in patients with different delusions of motor behavior. Additionally, it also sheds light on the mechanisms subserving bimanual coordination in the intact brain suggesting that action representation might be sufficient to produce these effects.
Kang, Nyeonju; Cauraugh, James H.
The purpose of this study was to investigate force variability generated by both the paretic and non-paretic hands during bimanual force control. Nine chronic stroke individuals and nine age-matched individuals with no stroke history performed a force control task with both hands simultaneously. The task involved extending the wrist and fingers at 5%, 25%, and 50% of maximum voluntary contraction. Bimanual and unimanual force variability during bimanual force control was determined by calcula...
Bimanual microincisional cataract surgery has been introduced recently as a technique for cataract surgery and it is gaining interest of many cataract surgeons in the world. Over the last few years many changes were made in the phacoemulsification machines and the intraocular lenses design which allowed bimanual microincisional cataract surgery to be safer and more efficient. The purpose of this review is to introduce the technique of bimanual microincisional cataract surgery and to review al...
Helene M Sisti
Full Text Available The acquisition of a new bimanual skill depends on several motor coordination constraints. To date, coordination constraints have often been tested relatively independently of one another, particularly with respect to isofrequency and multifrequency rhythms. Here, we used a new paradigm to test the interaction of multiple coordination constraints. Coordination constraints that were tested included temporal complexity, directionality, muscle grouping, and hand dominance. Twenty-two healthy young adults performed a bimanual dial rotation task that required left and right hand coordination to track a moving target on a computer monitor. Two groups were compared, either with or without four days of practice with augmented visual feedback. Four directional patterns were tested such that both hands moved either rightward (clockwise, leftward (counterclockwise, inward or outward relative to each other. Seven frequency ratios (3∶1, 2∶1, 3∶2, 1∶1, 2∶3. 1∶2, 1∶3 between the left and right hand were introduced. As expected, isofrequency patterns (1∶1 were performed more successfully than multifrequency patterns (non 1∶1. In addition, performance was more accurate when participants were required to move faster with the dominant right hand (1∶3, 1∶2 and 2∶3 than with the non-dominant left hand (3∶1, 2∶1, 3∶2. Interestingly, performance deteriorated as the relative angular velocity between the two hands increased, regardless of whether the required frequency ratio was an integer or non-integer. This contrasted with previous finger tapping research where the integer ratios generally led to less error than the non-integer ratios. We suggest that this is due to the different movement topologies that are required of each paradigm. Overall, we found that this visuomotor task was useful for testing the interaction of multiple coordination constraints as well as the release from these constraints with practice in the presence of
Long, Jinyi; Tazoe, Toshiki; Soteropoulos, Demetris S; Perez, Monica A
Interhemispheric interactions through the corpus callosum play an important role in the control of bimanual forces. However, the extent to which physiological connections between primary motor cortices are modulated during increasing levels of bimanual force generation in intact humans remains poorly understood. Here we studied coherence between electroencephalographic (EEG) signals and the ipsilateral cortical silent period (iSP), two well-known measures of interhemispheric connectivity between motor cortices, during unilateral and bilateral 10%, 40%, and 70% of maximal isometric voluntary contraction (MVC) into index finger abduction. We found that EEG-EEG coherence in the alpha frequency band decreased while the iSP area increased during bilateral compared with unilateral 40% and 70% but not 10% of MVC. Decreases in coherence in the alpha frequency band correlated with increases in the iSP area, and subjects who showed this inverse relation were able to maintain more steady bilateral muscle contractions. To further examine the relationship between the iSP and coherence we electrically stimulated the ulnar nerve at the wrist at the alpha frequency. Electrical stimulation increased coherence in the alpha frequency band and decreased the iSP area during bilateral 70% of MVC. Altogether, our findings demonstrate an inverse relation between alpha oscillations and the iSP during strong levels of bimanual force generation. We suggest that interactions between neural pathways mediating alpha oscillatory activity and transcallosal inhibition between motor cortices might contribute to the steadiness of strong bilateral isometric muscle contractions in intact humans. PMID:26538610
Garbarini, Francesca; Mastropasqua, Angela; Sigaudo, Monica; Rabuffetti, Marco; Piedimonte, Alessandro; Pia, Lorenzo; Rocca, Paola
A fruitful approach to the understanding the human awareness of action is the study of those pathologies in which some aspects of it are altered. Previous evidences showed that patients with schizophrenia tend to attribute someone else’ actions to their own, as internally, rather than externally, generated. Here, we asked whether schizophrenics have an “excessive” sense of agency, while observing others’ movements. We took advantage from the circles-lines task, known to show bimanual interferences. Twenty schizophrenics and 20 age-matched healthy controls were administered: (a) the bimanual version of the task: drawing lines with one hand and circles with the other; and (b) a modified version: drawing lines while observing the examiner drawing circles. In the bimanual version, patients and controls showed a comparable interference effect. In the observation version, schizophrenics, compared to controls, showed a significantly greater interference effect of the examiners’ hand drawing circles on the own hand drawing lines. This effect was significantly correlated to the strength of the positive symptoms (hallucinations and delusions) and to the alteration of the sense of agency, reported during the task. These findings suggest that an altered sense of agency, as shown by schizophrenics, can induce objective consequences on the motor system. PMID:27014005
Matthieu P. Boisgontier
Full Text Available Despite the intensive investigation of bimanual coordination, it remains unclear how directing vision toward either limb influences performance, and whether this influence is affected by age. To examine these questions, we assessed the performance of young and older adults on a bimanual tracking task in which they matched motor-driven movements of their right hand (passive limb with their left hand (active limb according to in-phase and anti-phase patterns. Performance in six visual conditions involving central vision, and/or peripheral vision of the active and/or passive limb was compared to performance in a no vision condition. Results indicated that directing central vision to the active limb consistently impaired performance, with higher impairment in older than young adults. Conversely, directing central vision to the passive limb improved performance in young adults, but less consistently in older adults. In conditions involving central vision of one limb and peripheral vision of the other limb, similar effects were found to those for conditions involving central vision of one limb only. Peripheral vision alone resulted in similar or impaired performance compared to the no vision condition. These results indicate that the locus of visual attention is critical for bimanual motor control in young and older adults, with older adults being either more impaired or less able to benefit from a given visual condition.
Regaiolli, Barbara; Spiezio, Caterina; Hopkins, William D
Assessing manual lateralization in non-human primates could be an optimal way to understand the adaptive value of this asymmetry in humans. Though many studies have investigated hand preferences in Old and New World monkeys and apes, fewer studies have considered manual lateralization in strepsirrhines, especially in experimental tasks. This study investigated hand preferences for a unimanual and a bimanual task of 17 captive ring-tailed lemurs (Lemur catta), housed at Parco Natura Viva (VR), Italy. The effect of age on handedness has been also investigated. The lemurs were tested on a unimanual task, in which subjects were restricted to using one hand to retrieve the food inside an apparatus, and on a bimanual task, in which lemurs had to use one hand to keep the apparatus door open while reaching with the other hand to retrieve the food inside it. At the population-level, our results revealed an asymmetrical hand use distribution, in particular a bias toward a right hand preference for food reaching in both the unimanual and the bimanual tasks. Furthermore, at the individual-level, the bimanual task seems to elicit a greater hand preference than the unimanual task. Results of this study underline the importance of experimental tasks in determining hand preference in strepsirrhines. Furthermore, as bimanual tasks elicited a stronger degree of lateralization, they appear to be more suited to investigate manual laterality. Finally, findings from this study highlight the presence of a right hand preference in ring-tailed lemurs, shedding new light on the evolution of human right handedness. Am. J. Primatol. 78:851-860, 2016. © 2016 Wiley Periodicals, Inc. PMID:27078687
Right-hand dominance is widely considered to be a uniquely human trait. Whether nonhuman primates exhibit similar population-level hand preferences remains a topic of considerable debate. Despite extensive research focusing on laterality in nonhuman primates, our interpretation of these studies is limited due to methodological issues including the lack of a common measure of hand preference and the use of tasks that may not be reliable indicators of handedness. The use of consistent methods between studies is necessary to enable comparisons within and between species and allow for more general conclusions to be drawn from these results. The present study replicates methods used in recent research reporting population-level right-handedness in captive gorillas (Meguerditchian et al.,2010). Observational data were collected on hand preference for unimanual and bimanual feeding in 14 captive western lowland gorillas (Gorilla gorilla gorilla). Individual-level preferences were found, primarily for bimanual feeding; however, the data reveal no group-level directional bias (contra Meguerditchian et al.). Like the study by Meguerditchian et al. (2010), though, bimanual feeding revealed significantly stronger hand preferences than unimanual reaching, and age, sex, group membership, or rearing history had no effect on hand preference. Finally, variations in diet and corresponding grip type between studies suggest that hand preferences may vary across bimanual tasks depending on grip morphology. This study aims to contribute to our existing knowledge of primate laterality by increasing the number of individuals investigated using methods that allow for comparisons with similar research. PMID:22639326
Juravle, Georgiana; Spence, Charles
This thesis focuses on tactile perception and aims at a comprehensive analysis of its characteristics over the time-course of various goal-directed movements. Tactile perception is assessed by means of discrimination and detection paradigms, as well as event-related potentials (ERPs). The main question investigated throughout the thesis is: ‘What changes in tactile perception, if any, take place over the time course of a goal-directed movement?’ In Chapter 2, the mechanisms related to such id...
Strauss, Soeren; Woodgate, Philip J W; Sami, Saber A; Heinke, Dietmar
We present an extension of a neurobiologically inspired robotics model, termed CoRLEGO (Choice reaching with a LEGO arm robot). CoRLEGO models experimental evidence from choice reaching tasks (CRT). In a CRT participants are asked to rapidly reach and touch an item presented on the screen. These experiments show that non-target items can divert the reaching movement away from the ideal trajectory to the target item. This is seen as evidence attentional selection of reaching targets can leak into the motor system. Using competitive target selection and topological representations of motor parameters (dynamic neural fields) CoRLEGO is able to mimic this leakage effect. Furthermore if the reaching target is determined by its colour oddity (i.e. a green square among red squares or vice versa), the reaching trajectories become straighter with repetitions of the target colour (colour streaks). This colour priming effect can also be modelled with CoRLEGO. The paper also presents an extension of CoRLEGO. This extension mimics findings that transcranial direct current stimulation (tDCS) over the motor cortex modulates the colour priming effect (Woodgate et al., 2015). The results with the new CoRLEGO suggest that feedback connections from the motor system to the brain's attentional system (parietal cortex) guide visual attention to extract movement-relevant information (i.e. colour) from visual stimuli. This paper adds to growing evidence that there is a close interaction between the motor system and the attention system. This evidence contradicts the traditional conceptualization of the motor system as the endpoint of a serial chain of processing stages. At the end of the paper we discuss CoRLEGO's predictions and also lessons for neurobiologically inspired robotics emerging from this work. PMID:26667353
Klein, Alexander; Sacrey, Lori-Ann R; Dunnett, Stephen B; Whishaw, Ian Q; Nikkhah, Guido
Huntington's disease (HD) causes severe motor impairments that are characterized by chorea, dystonia, and impaired fine motor control. The motor deficits include deficits in the control of the forelimb, but as yet there has been no comprehensive assessment of the impairments in arm, hand and digit movements as they are used in every-day tasks. The present study investigated the reaching of twelve HD subjects and twelve age-matched control subjects on a reach-to-eat task. The subjects were asked to reach for a small food item, with the left or the right hand, and then bring it to the mouth for eating. The task assesses the major features of skilled forelimb use, including orienting to a target, transport of the hand to a target, use of a precision grasp of the target, limb withdrawal to the mouth, and release of the food item into the mouth, and the integration of the movements into a smooth act. The movements were analyzed frame-by-frame by scoring the video record using an established movement element rating scale and by biometric analysis to describe limb trajectory. All HD subjects displayed greater reliance on more proximal movements in reaching. They also displayed overall jerkiness, a significant impairment in end point error correction (i.e. no smooth trajectories), deficits in timing and terminating motion (overshooting the target), impairments in rotation of the hand, abnormalities in grasping, and impairments in releasing the food item to the mouth. Although impairment in the control of the distal segments of the limb was common to all subjects, the intrusion of choreatic movements produced a pattern of highly variable performance between subjects. The quantification of reaching performance as measured by this analysis provides new insights into the impairments of HD subjects, allows an easily administered and inexpensive way to document the many skilled limb movement abnormalities, and relates the impairments to a real-world context. The protocol can
Grimm, Florian; Naros, Georgios; Gharabaghi, Alireza
Assistive technology allows for intensive practice and kinematic measurements during rehabilitation exercises. More recent approaches attach a gravity-compensating multi-joint exoskeleton to the upper extremity to facilitate task-oriented training in three-dimensional space with virtual reality feedback. The movement quality, however, is mostly captured through end-point measures that lack information on proximal inter-joint coordination. This limits the differentiation between compensation strategies and genuine restoration both during the exercise and in the course of rehabilitation. We extended in this proof-of-concept study a commercially available seven degree-of-freedom arm exoskeleton by using the real-time sensor data to display a three-dimensional multi-joint visualization of the user's arm. Ten healthy subjects and three severely affected chronic stroke patients performed reach-to-grasp exercises resembling activities of daily living assisted by the attached exoskeleton and received closed-loop online feedback of the three-dimensional movement in virtual reality. Patients in this pilot study differed significantly with regard to motor performance (accuracy, temporal efficiency, range of motion) and movement quality (proximal inter-joint coordination) from the healthy control group. In the course of 20 training and feedback sessions over 4 weeks, these pathological measures improved significantly toward the reference parameters of healthy participants. It was moreover feasible to capture the evolution of movement pattern kinematics of the shoulder and elbow and to quantify the individual degree of natural movement restoration for each patient. The virtual reality visualization and closed-loop feedback of joint-specific movement kinematics makes it possible to detect compensation strategies and may provide a tool to achieve the rehabilitation goals in accordance with the individual capacity for genuine functional restoration; a proposal that warrants
Ridderikhoff, Arne; Peper, C. E.; Beek, Peter J.
Studies of rhythmic bimanual coordination under dual-task conditions revealed (1) a dependence of secondary task performance on the stability of coordinative tasks, in that secondary task performance was better during in-phase than antiphase coordination, and (2) a shift in the mean relative phasing between the limbs compared to single-task…
Serbruyns, Leen; Gooijers, Jolien; Caeyenberghs, Karen; Meesen, Raf; Cuypers, Koen; Sisti, Helene; Leemans, Alexander; Swinnen, Stephan
Age-related changes in the microstructural organization of the corpus callosum (CC) may explain declines in bimanual motor performance associated with normal aging. We used diffusion tensor imaging in young (n = 33) and older (n = 33) adults to investigate the microstructural organization of seven specific CC subregions (prefrontal, premotor, primary motor, primary sensory, parietal, temporal and occipital). A set of bimanual tasks was used to assess various aspects of bimanual motor function...
Morales, Ricardo; Badesa, Francisco J.; García-Aracil, Nicolás; Bormann, Richard; Fischer, Jan; Graf, Birgit
The present paper presents the ongoing research undertaken as a research experiment, called HERMES, inside Echord european integrated project framework. The goal of the HERMES experiment is to study, analyze and finally implement the packaging of shoes on a robot system that mimics the required degree of flexibility and dexterity provided by the human workers. The use of a bimanual system with anthropomorphic hands has been chosen as it could also be applied to solve other processes of simila...
Hopkins, William D; Phillips, Kimberley A; Bania, Amanda;
-level right-handedness in chimpanzees, bonobos and gorillas, but left-handedness in orangutans. Directional biases in handedness were consistent across independent samples of apes within each genus. We suggest that, contrary to previous claims, population-level handedness is evident in great apes but differs......Whether or not nonhuman primates exhibit population-level handedness remains a topic of considerable scientific debate. Here, we examined handedness for coordinated bimanual actions in a sample of 777 great apes including chimpanzees, bonobos, gorillas, and orangutans. We found population...
Coey, Charles A; Washburn, Auriel; Hassebrock, Justin; Richardson, Michael J
The current study was designed to investigate complexity matching during syncopated behavioral coordination. Participants either tapped in (bimanual) syncopation using their two hands, or tapped in (interpersonal) syncopation with a partner, with each participant using one of their hands. The time series of inter-tap intervals (ITI) from each hand were submitted to fractal analysis, as well as to short-term and multi-timescale cross-correlation analyses. The results demonstrated that the fractal scaling of one hand's ITI was strongly correlated to that of the other hand, and this complexity matching effect was stronger in the bimanual condition than in the interpersonal condition. Moreover, the degree of complexity matching was predicted by the strength of short-term cross-correlation and the stability of the asynchrony between the two tapping series. These results suggest that complexity matching is not specific to the inphase synchronization tasks used in past research, but is a general result of coordination between complex systems. PMID:26840612
Dexterous and autonomous manipulation is a key technology for the personal and service robots of the future. Advances in Bimanual Manipulation edited by Bruno Siciliano provides the robotics community with the most noticeable results of the four-year European project DEXMART (DEXterous and autonomous dual-arm hand robotic manipulation with sMART sensory-motor skills: A bridge from natural to artificial cognition). The volume covers a host of highly important topics in the field, concerned with modelling and learning of human manipulation skills, algorithms for task planning, human-robot interaction, and grasping, as well as hardware design of dexterous anthropomorphic hands. The results described in this five-chapter collection are believed to pave the way towards the development of robotic systems endowed with dexterous and human-aware dual-arm/hand manipulation skills for objects, operating with a high degree of autonomy in unstructured real-world environments.
Vegter, Riemer J. K.; Lamoth, Claudine J.; de Groot, Sonja; Veeger, Dirkjan H. E. J.; van der Woude, Lucas H. V.
Background: Handrim wheelchair propulsion is a complex bimanual motor task. The bimanually applied forces on the rims determine the speed and direction of locomotion. Measurements of forces and torques on the handrim are important to study status and change of propulsion technique (and consequently
Vegter, R.J.K.; Lamoth, C.J.; De Groot, S.; Veeger, H.E.J.; Van der Woude, L.H.V.
Background Handrim wheelchair propulsion is a complex bimanual motor task. The bimanually applied forces on the rims determine the speed and direction of locomotion. Measurements of forces and torques on the handrim are important to study status and change of propulsion technique (and consequently m
Gooijers, Jolien; Caeyenberghs, Karen; Sisti, Helene M.; Geurts, Monique; Heitger, Marcus H.; Leemans, Alexander; Swinnen, Stephan P.
When manipulating objects with both hands, the corpus callosum (CC) is of paramount importance for interhemispheric information exchange. Hence, CC damage results in impaired bimanual performance. Here, healthy young adults performed a complex bimanual dial rotation task with or without augmented vi
Just, Agnès; Bernier, O.; Marcel, Sébastien
In this paper, we address the problem of the recognition of isolated complex mono- and bi-manual hand gestures. In the proposed system, hand gestures are represented by the 3D trajectories of blobs obtained by tracking colored body parts. In this paper, we study the results obtained on a complex database of mono- and bi-manual gestures. These results are obtained by using Input/Output Hidden Markov Model (IOHMM), implemented within the framework of an open source machine learning library, and...
Just, Agnès; Bernier, O.; Marcel, Sébastien
In this paper, we address the problem of the recognition of isolated complex mono- and bi-manual hand gestures. In the proposed system, hand gestures are represented by the 3D trajectories of blobs. Blobs are obtained by tracking colored body parts in real-time using the EM algorithm. In most of the studies on hand gestures, only small vocabularies have been used. In this paper, we study the results obtained on a more complex database of mono- and bi-manual gestures. These results are obtaine...
Hilgers, F J M; Dirven, R; Jacobi, I; van den Brekel, M W M
This study investigated whether trachea pressures during brass instrument play of laryngectomised patients are within the range of those measured during tracheoesophageal voicing, and whether application of an automatic speaking valve can 'free' both hands to play a brass instrument. Objective assessment of voicing and music playing parameters was carried out in 2 laryngectomised patients with a low-pressure indwelling voice-prosthesis able to play brass instruments (tenor horn and slide trombone): sound pressure levels in dB, maximum phonation time in seconds and trachea pressures in mmHg; videofluoroscopy, stroboscopy and digital high speed endoscopy to assess neoglottis vibration and opening. The dynamic range of the voice in the patients was 29 and 20 dB, and maximum phonation time was 22 and 19 sec, respectively; intratracheal pressures during voicing varied from 7 mmHg for the softest /a/ to 49 mmHg for the loudest /a/. For brass instrument play, the intratracheal pressures varied from 14 mmHg for the softest tone to 48 mmHg for the loudest tone. Imaging confirmed earlier findings that the neoglottis is closing and vibrating during voicing and remains 'open' without vibrations during music play, indicating good neoglottis control and innervation. From these objective measurements, we can conclude that trachea pressures during brass instrument play are within physiological ranges for tracheoesophageal voicing with a low-pressure indwelling voice-prosthesis. Furthermore, it was shown that application of a stable baseplate for retaining an automatic speaking valve and an additional customisable 'neck brace' makes bimanual play possible again. PMID:26246666
Cochet, Helene; Jover, Marianne; Vauclair, Jacques
This study investigated the development of hand preference for bimanual manipulative activities and pointing gestures in toddlers observed longitudinally over a 5-month period, in relation to language acquisition. The lexical spurt was found to be accompanied by an increase in the right-sided bias for pointing but not for manipulation. Moreover,…
Full Text Available Neuroplasticity studies examining children with hemiparesis (CH have focused predominantly on unilateral interventions. CH also have bimanual coordination impairments with bimanual interventions showing benefits. We explored neuroplasticity following hand-arm bimanual intensive therapy (HABIT of 60 hours in twelve CH (6 females, mean age 11 ± 3.6 y. Serial behavioral evaluations and MR imaging including diffusion tensor (DTI and functional (fMRI imaging were performed before, immediately after, and at 6-week follow-up. Manual skills were assessed repeatedly with the Assisting Hand Assessment, Children’s Hand Experience Questionnaire, and Jebsen-Taylor Test of Hand Function. Beta values, indicating the level of activation, and lateralization index (LI, indicating the pattern of brain activation, were computed from fMRI. White matter integrity of major fibers was assessed using DTI. 11/12 children showed improvement after intervention in at least one measure, with 8/12 improving on two or more tests. Changes were retained in 6/8 children at follow-up. Beta activation in the affected hemisphere increased at follow-up, and LI increased both after intervention and at follow-up. Correlations between LI and motor function emerged after intervention. Increased white matter integrity was detected in the corpus callosum and corticospinal tract after intervention in about half of the participants. Results provide first evidence for neuroplasticity changes following bimanual intervention in CH.
Weinstein, Maya; Myers, Vicki; Green, Dido; Schertz, Mitchell; Shiran, Shelly I.; Geva, Ronny; Artzi, Moran; Gordon, Andrew M.; Fattal-Valevski, Aviva; Ben Bashat, Dafna
Neuroplasticity studies examining children with hemiparesis (CH) have focused predominantly on unilateral interventions. CH also have bimanual coordination impairments with bimanual interventions showing benefits. We explored neuroplasticity following hand-arm bimanual intensive therapy (HABIT) of 60 hours in twelve CH (6 females, mean age 11 ± 3.6 y). Serial behavioral evaluations and MR imaging including diffusion tensor (DTI) and functional (fMRI) imaging were performed before, immediately after, and at 6-week follow-up. Manual skills were assessed repeatedly with the Assisting Hand Assessment, Children's Hand Experience Questionnaire, and Jebsen-Taylor Test of Hand Function. Beta values, indicating the level of activation, and lateralization index (LI), indicating the pattern of brain activation, were computed from fMRI. White matter integrity of major fibers was assessed using DTI. 11/12 children showed improvement after intervention in at least one measure, with 8/12 improving on two or more tests. Changes were retained in 6/8 children at follow-up. Beta activation in the affected hemisphere increased at follow-up, and LI increased both after intervention and at follow-up. Correlations between LI and motor function emerged after intervention. Increased white matter integrity was detected in the corpus callosum and corticospinal tract after intervention in about half of the participants. Results provide first evidence for neuroplasticity changes following bimanual intervention in CH. PMID:26640717
Serbruyns, L.; Gooijers, J.; Caeyenberghs, K.; Meesen, R. L.; Cuypers, K.; Sisti, H. M.; Leemans, A.; Swinnen, Stephan P.
Age-related changes in the microstructural organization of the corpus callosum (CC) may explain declines in bimanual motor performance associated with normal aging. We used diffusion tensor imaging in young (n = 33) and older (n = 33) adults to investigate the microstructural organization of seven s
Mulvey, G. M.; Ringenbach, S. D. R.; Jung, M. L.
Background: Research on unimanual tasks suggested that motor asymmetries between hands may be reduced in people with Down syndrome. Our study examined handedness (as assessed by hand performance) and perceptual-motor integration effects on bimanual coordination. Methods: Adults with Down syndrome (13 non-right-handed, 22 right-handed), along with…
The functional integrity of the bimanual neuro-motor system of Parkinson's disease (PD) subjects (stage II) compared to controls (2 X n = 16) was evaluated by measures of coordination stability of tapping in in-phase, anti-phase, and 90 degrees -phase. Recently, intentional influence was modeled as
Hopkins, William D.; Rabinowitz, Deborah M.
Hand preference for tool use was assessed in a sample of captive chimpanzees (Pan troglodytes). Whether the subjects solved the tool task using either a unimanual or coordinated bimanual strategy was manipulated in the chimpanzees. No population-level hand preference was found for tool use when unimanual strategies were used by the chimpanzees. However, a population-level right-hand bias was found when coordinated bimanual actions were required of the chimpanzees. A significant correlation wa...
Volcic, Robert; Vishwanath, Dhanraj; Domini, Fulvio
While binocular viewing of 2D pictures generates an impression of 3D objects and space, viewing a picture monocularly through an aperture produces a more compelling impression of depth and the feeling that the objects are "out there", almost touchable. Here, we asked observers to actually reach into pictorial space under both binocular- and monocular-aperture viewing. Images of natural scenes were presented at different physical distances via a mirror-system and their retinal size was kept constant. Targets that observers had to reach for in physical space were marked on the image plane, but at different pictorial depths. We measured the 3D position of the index finger at the end of each reach-to-point movement. Observers found the task intuitive. Reaching responses varied as a function of both pictorial depth and physical distance. Under binocular viewing, responses were mainly modulated by the different physical distances. Instead, under monocular viewing, responses were modulated by the different pictorial depths. Importantly, individual variations over time were minor, that is, observers conformed to a consistent pictorial space. Monocular viewing of 2D pictures thus produces a compelling experience of an immersive space and tangible solid objects that can be easily explored through motor actions.
Full Text Available Cataract surgery has evolved over the past few decades with progressive decrease in the size of the incision. Originally from 12 mm intracapsular incision to bimanual phacoemulsification (Micro - Phaco that has incision size of just 700 microns. In the pres ent comparative PROSPECTIVE study best corrected visual acuity postoperatively and surgically induced astigmatism were compared in routine Phacoemulsification technique and bimanual phaco (Micro - Phaco 60 eyes were studied. There was no statistically signi ficant difference in postoperative best corrected visual acuity (BCVA of patients operated with Micro - Phaco or routine Phacoemulsification. There was difference in surgically induced astigmatism (SIA ; average SIA in microphaco was 0.5972 as against 0.832 8 in routine Phacoemulsification.
Feugère, Lionel; D'Alessandro, Christophe
ISSN 2220-4806. International audience Digitartic, a system for bi-manual gestural control of Vowel- Consonant-Vowel performative singing synthesis is presented. This system is an extension of a real-time gesture-controlled vowel singing instrument developed in the Max MSP language. In addition to pitch, vowels and voice strength controls, Digitartic is designed for gestural control of articulation parameters, including various places and manners of articulation. The phases of articulat...
Foucault, Cédric; Micaux, Manfred; Bonnet, David; Beaudouin-Lafon, Michel
SPad is a new bimanual interaction technique designed to improve productivity on multi-touch tablets: the user activates quasimodes with the thumb of the non-dominant hand while holding the device with that hand and interacts with the content with the dominant hand. The paper describes the design of SPad and a tablet application that demonstrates how it enables faster, more direct and more powerful interaction without increasing complexity.
Byeon, Suk Ho; Kwon, Oh W
Lens extraction during vitrectomy is sometimes necessary to obtain an adequate view of the retina. Currently, phacoemulsification through a clear corneal incision with implantation of a foldable intraocular lens has become the preferred technique for cataract extraction during pars plana vitrectomy. The authors described the technique of lensectomy using a bimanual microincisional cataract surgery technique during pars plana vitrectomy and insertion of the intraocular lens at the end of surgery, which has several advantages over conventional coaxial phacoemulsification procedures. PMID:19205506
Lisa Pauwels; Swinnen, Stephan P.; Iseult A M Beets
The contextual interference (CI) effect is a robust phenomenon in the (motor) skill learning literature. However, CI has yielded mixed results in complex task learning. The current study addressed whether the CI effect is generalizable to bimanual skill learning, with a focus on the temporal evolution of memory processes. In contrast to previous studies, an extensive training schedule, distributed across multiple days of practice, was provided. Participants practiced three frequency ratios ac...
Lafe, Charley W; Pacheco, Matheus M; Newell, Karl M
The effect of the intermittency of visual information in the bimanual coordination of an isometric force coordination task was investigated as a function of criterion force level. Eight levels of visual information intermittency (.2-25.6 Hz) were used in blocked fashion at each force level. Participants were required to produce a constant force output matching as accurately as possible the criterion force target. The results showed that performance improved as the intermittency of visual information was reduced-this effect being a function of force level. The distribution of the relative phase through the trial revealed a preference for the two hands to be coupled together (in-phase) at the slower rates of visual presentation (~.2 Hz). However, as the rate of visual feedback was increased (up to ~25.6 Hz), there was a transition to predominantly a negative correlation pattern (anti-phase). The pattern of bimanual coordination in this isometric tracking task is driven by the availability of information for error correction and the interactive influence of perceptual-motor constraints. PMID:26960740
Iandolo, Riccardo; Squeri, Valentina; De Santis, Dalia; Giannoni, Psiche; Morasso, Pietro; Casadio, Maura
Is there any difference between matching the position of the hands by asking the subjects to move them to the same spatial location or to mirror-symmetric locations with respect to the body midline? If the motion of the hands were planned in the extrinsic space, the mirror-symmetric task would imply an additional challenge, because we would need to flip the coordinates of the target on the other side of the workspace. Conversely, if the planning were done in intrinsic coordinates, in order to move both hands to the same spot in the workspace, we should compute different joint angles for each arm. Even if both representations were available to the subjects, the two tasks might lead to different results, providing some cue on the organization of the "body schema". In order to answer such questions, the middle fingertip of the non-dominant hand of a population of healthy subjects was passively moved by a manipulandum to 20 different target locations. Subjects matched these positions with the middle fingertip of their dominant hand. For most subjects, the matching accuracy was higher in the extrinsic modality both in terms of systematic error and variability, even for the target locations in which the configuration of the arms was the same for both modalities. This suggests that the matching performance of the subjects could be determined not only by proprioceptive information but also by the cognitive representation of the task: expressing the goal as reaching for the physical location of the hand in space is apparently more effective than requiring to match the proprioceptive representation of joint angles. PMID:25741268
Kantak, Shailesh S.; Jones-Lush, Lauren M.; Narayanan, Priya; Judkins, Timothy N.; Wittenberg, George F.
Goal-directed reaching is important for activities of daily living. Populations of neurons in the primary motor cortex (M1) that project to spinal motor circuits are known to represent kinematics of reaching movements. We investigated whether repetitive practice of goal-directed reaching movements induces use-dependent plasticity of those kinematic characteristics, in a manner similar to finger movements, as had been shown previously. Transcranial magnetic stimulation (TMS) was used over the ...
Bogaerts, H; Buekers, MJ; Zaal, FT; Swinnen, SP
Two experiments are reported in which bimanual coordination tasks were performed under correct and transformed visual feedback conditions. Participants were to generate cyclical line-drawing patterns, with varying degrees of coordinative stability, while perceiving correct or transformed visual info
Reichenbach, Alexandra; Bresciani, Jean-Pierre; Bülthoff, Heinrich H;
The vestibular system constitutes the silent sixth sense: It automatically triggers a variety of vital reflexes to maintain postural and visual stability. Beyond their role in reflexive behavior, vestibular afferents contribute to several perceptual and cognitive functions and also support...... voluntary control of movements by complementing the other senses to accomplish the movement goal. Investigations into the neural correlates of vestibular contribution to voluntary action in humans are challenging and have progressed far less than research on corresponding visual and proprioceptive...... involvement. Here, we demonstrate for the first time with event-related TMS that the posterior part of the right medial intraparietal sulcus processes vestibular signals during a goal-directed reaching task with the dominant right hand. This finding suggests a qualitative difference between the processing...
Rachwani, Jaya; Santamaria, Victor; Saavedra, Sandra L.; Wood, Stacy; Porter, Francine; Woollacott, Marjorie H.
This study explored the influence of an external support at the thoracic and pelvic level of the trunk on the success of reaching, postural stability and reaching kinematics while infants reached for a toy. Seventeen infants (4–6 months) were clustered into two groups according to their trunk control assessed with the Segmental Assessment of Trunk Control (SATCo). Major differences were seen between groups with pelvic support, whereas with thoracic support, all infants showed similar quality reaching behaviours. With the external pelvic support, infants who had acquired trunk control in the lumbar region were more accurate in their reaching movements (less movement time, improved straightness of reach, less movement units and path length per movement unit) and were more stable (decreased trunk and head displacement) during a reach than infants that had only acquired trunk control in the thoracic region. These results support the hypothesis that trunk control influences the quality of reaching behaviour. PMID:23681292
U.S. Environmental Protection Agency — The Reach Address Database (RAD) stores the reach address of each Water Program feature that has been linked to the underlying surface water features (streams,...
Full Text Available CONTEXTUALIZAÇÃO: Estudos têm identificado que as propriedades dos objetos induzem os ajustes no alcance; no entanto, poucos investigaram a influência específica do tamanho e rigidez dos objetos em lactentes jovens. OBJETIVO: Verificar se lactentes de 4 a 6 meses realizam ajustes proximais e distais ao alcançarem objetos de diferentes tamanhos e rigidez. MÉTODOS: Nove lactentes saudáveis foram posicionados em uma cadeira inclinada a 50º. Quatro objetos foram apresentados, um rígido grande (RG, um rígido pequeno (RP, um maleável grande (MG e um maleável pequeno (MP, por um período de 1 minuto cada. Em um total de 384 alcances, foram analisados os ajustes proximais (alcance uni e bimanual e distais (orientação da mão horizontal, vertical e oblíqua; mão aberta, fechada e semi-aberta e o sucesso do alcance dos objetos. RESULTADOS: Constatou-se ajuste bimanual para o objeto RG e unimanual para os demais. A orientação da mão oblíqua foi predominante no toque dos objetos, enquanto para a preensão dos mesmos, a predominância foi a vertical, principalmente para o objeto RG. A orientação horizontal não foi observada na preensão do objeto RG. A mão semi-aberta foi mais freqüente no início do alcance para todos os objetos, enquanto no toque do objeto RG a mão aberta foi predominante. O sucesso do alcance foi maior para os objetos maleáveis (MG, MP do que para os rígidos (RG e RP. CONCLUSÃO: Lactentes jovens estudados são capazes de planejar e ajustar seus movimentos baseados na percepção das propriedades físicas dos objetos, o que sugere interação percepção-ação.BACKGROUND: Studies have identified that object properties lead to adjustments to reaching. However, few have investigated the specific influence of object size and rigidity among young infants. OBJECTIVE: To verify whether four to six-month-old infants make proximal and distal adjustments when reaching for objects of different sizes and rigidity. METHOD
Kuo, Hsing-Ching; Gordon, Andrew M.; Henrionnet, Aline; Hautfenne, Sylvie; Friel, Kathleen M.; Bleyenheuft, Yannick
Children with unilateral spastic cerebral palsy (USCP) often have tactile impairments. Intensive bimanual training improves the motor abilities, but the effects on the sensory system have not been studied. Here we compare the effects of bimanual training with and without tactile training on tactile impairments. Twenty children with USCP (6–15.5 years; MACS: I–III) were randomized to receive either bimanual therapy (HABIT) or HABIT + tactile training (HABIT + T). All participants received 82 h of standardized HABIT. In addition 8 sessions of 1 h were provided to both groups. The HABIT + T group received tactile training (without vision) using materials of varied shapes and textures. The HABIT group received training with the same materials without tactile directed training (full vision). Primary outcomes included grating orientation task/GOT and stereognosis. Secondary outcomes included two-point discrimination/TPD, Semmes-Weinstein monofilaments/SWM. The GOT improved in both groups after training, while stereognosis of the more-affected hand tended to improve (but p = 0.063). No changes were found in the TPD and the SWM. There were no group × test interactions for any measure. We conclude tactile spatial resolution can improve after bimanual training. Either intensive bimanual training alone or incorporation of materials with a diversity of shapes/textures may drive these changes. PMID:26698408
Osumi, Michihiro; Sumitani, Masahiko; Wake, Naoki; Sano, Yuko; Ichinose, Akimichi; Kumagaya, Shin-Ichiro; Kuniyoshi, Yasuo; Morioka, Shu
The relation between phantom limb pain (PLP) and the movement representation of a phantom limb remains controversial in several areas of neurorehabilitation, although there are a few studies in which the representation of phantom limb movement was precisely evaluated. We evaluated the structured movement representation of a phantom limb objectively using a bimanual circle-line coordination task. We then investigated the relation between PLP and the structured movement representation. Nine patients with a brachial plexus avulsion injury were enrolled who perceived a phantom limb and had neuropathic pain. While blindfolded, the participants repeatedly drew vertical lines using the intact hand and intended to draw circles using the phantom limb simultaneously. "Drawing of circles" by the phantom limb resulted in an oval transfiguration of the vertical lines ("bimanual coupling" effect). We used an arbitrary ovalization index (OI) to quantify the oval transfiguration. When the OI neared 100%, the trajectory changed toward becoming more circular. A significant negative correlation was observed between the intensity of PLP and the OI (r=-0.66, pphantom limb are necessary for alleviating PLP. PMID:26272300
Full Text Available The contextual interference (CI effect is a robust phenomenon in the (motor skill learning literature. However, CI has yielded mixed results in complex task learning. The current study addressed whether the CI effect is generalizable to bimanual skill learning, with a focus on the temporal evolution of memory processes. In contrast to previous studies, an extensive training schedule, distributed across multiple days of practice, was provided. Participants practiced three frequency ratios across three practice days following either a blocked or random practice schedule. During the acquisition phase, better overall performance for the blocked practice group was observed, but this difference diminished as practice progressed. At immediate and delayed retention, the random practice group outperformed the blocked practice group, except for the most difficult frequency ratio. Our main finding is that the random practice group showed superior performance persistence over a one week time interval in all three frequency ratios compared to the blocked practice group. This study contributes to our understanding of learning, consolidation and memory of complex motor skills, which helps optimizing training protocols in future studies and rehabilitation settings.
Full Text Available Disabilities after neural injury, such as stroke, bring tremendous burden to patients, families and society. Besides the conventional constrained-induced training with a paretic arm, bilateral rehabilitation training involves both the ipsilateral and contralateral sides of the neural injury, fitting well with the fact that both arms are needed in common activities of daily living (ADLs, and can promote good functional recovery. In this work, the fusion of a gesture sensor and a haptic sensor with force feedback capabilities has enabled a bilateral rehabilitation training therapy. The Leap Motion gesture sensor detects the motion of the healthy hand, and the omega.7 device can detect and assist the paretic hand, according to the designed cooperative task paradigm, as much as needed, with active force feedback to accomplish the manipulation task. A virtual scenario has been built up, and the motion and force data facilitate instantaneous visual and audio feedback, as well as further analysis of the functional capabilities of the patient. This task-oriented bimanual training paradigm recruits the sensory, motor and cognitive aspects of the patient into one loop, encourages the active involvement of the patients into rehabilitation training, strengthens the cooperation of both the healthy and impaired hands, challenges the dexterous manipulation capability of the paretic hand, suits easy of use at home or centralized institutions and, thus, promises effective potentials for rehabilitation training.
Pauwels, Lisa; Swinnen, Stephan P; Beets, Iseult A M
The contextual interference (CI) effect is a robust phenomenon in the (motor) skill learning literature. However, CI has yielded mixed results in complex task learning. The current study addressed whether the CI effect is generalizable to bimanual skill learning, with a focus on the temporal evolution of memory processes. In contrast to previous studies, an extensive training schedule, distributed across multiple days of practice, was provided. Participants practiced three frequency ratios across three practice days following either a blocked or random practice schedule. During the acquisition phase, better overall performance for the blocked practice group was observed, but this difference diminished as practice progressed. At immediate and delayed retention, the random practice group outperformed the blocked practice group, except for the most difficult frequency ratio. Our main finding is that the random practice group showed superior performance persistence over a one week time interval in all three frequency ratios compared to the blocked practice group. This study contributes to our understanding of learning, consolidation and memory of complex motor skills, which helps optimizing training protocols in future studies and rehabilitation settings. PMID:24960171
Viswanathan, Priya; Whitall, Jill; Kagerer, Florian A
Reaching toward an object usually consists of a sequence of elemental actions. Using a reaching task sequence, the authors investigated how task elements of that sequence affected feedforward and feedback components of the reaching phase of the movement. Nine right-handed adults performed, with their dominant and nondominant hands, 4 tasks of different complexities: a simple reaching task; a reach-to-grasp task; a reach-to-grasp and lift object task; and a reach-to-grasp, lift, and place object task. Results showed that in the reach-to-grasp and lift object task more time was allocated to the feedforward component of the reach phase, while latency between the task elements decreased. We also found between-hand differences, supporting previous findings of increased efficiency of processing planning-related information in the preferred hand. The presence of task-related modifications supports the concept of contextual effects when planning a movement. PMID:27254601
Garrison, Joe; And Others
As a part of the REACH (Refrigeration, Electro-Mechanical, Air-Conditioning, Heating) electromechanical cluster, this student manual contains individualized instructional units in the area of air conditioning. The instructional units focus on air conditioning fundamentals, window air conditioning, system and installation, troubleshooting and…
Snow, Rufus; And Others
As a part of the REACH (Refrigeration, Electro-Mechanical, Air-Conditioning, Heating) electromechanical cluster, this student manual contains individualized instructional units in the area of refrigeration. The instructional units focus on refrigeration fundamentals, tubing and pipe, refrigerants, troubleshooting, window air conditioning, and…
Everyday Fitness Ideas from the National Institute on Aging at NIH www.nia.nih.gov/Go4Life Reaching Your Fitness Goals You’ll begin to see results in ... longer, and more easily. As you increase your fitness level, you also might find that you need ...
Dunn, P A; Rogers, D K
To investigate the effect of sensory imagery on subsequent movement, a unilateral Fleldenkrais lesson of imaging a soft bristle brush passing over one half of the body and in which no movement occurred, was given to 12 naive subjects. Forward flexion for each side of the body was measured at a sit-and-reach box. For 8 and 10 subjects who reported the perception of a side as being longer and lighter following the sensory imagery, there was also a significant increase in the forward flexion range on that side. PMID:11153843
Bardo, Ameline; Pouydebat, Emmanuelle; Meunier, Hélène
Approximately 90% of the human population is right-handed. The emergence of this hand preference in humans is thought to be linked to the ability to execute complex tasks and habitual bipedalism. In order to test these hypotheses, the present study explored, for the first time, hand preference in relation to both body posture (seated and bipedal) and task complexity (bimanual coordination and two tool use tasks of different complexity) in bonobos (Pan paniscus). Few studies have explored the effects of both posture and task complexity on handedness, and investigations with bonobos are scarce, particularly studies on tool use. Our study aims to overcome such a gap by addressing two main questions: 1) Does a bipedal posture increase the strength of hand preference and/or create a directional bias to the use of the right hand? 2) Independent of body posture, does task complexity increase the strength of the hand preference and/or create a directional bias to the use of the right hand? Our results show that independent of body posture, the more complex the task, the more lateralization occurred. Moreover, subjects tended to be right-handed for tasks involving tool use. However, posture had no significant effect on hand preference in the tasks tested here. Therefore, for a given task, bonobos were not more lateralized in a bipedal posture than in a seated one. Task complexity might thus have contributed more than bipedal posture to the emergence of human lateralization and the preponderance of right-handedness, although a larger sample size and more data are needed to be conclusive. PMID:25870160
Kantak, S S; Jones-Lush, L M; Narayanan, P; Judkins, T N; Wittenberg, G F
Goal-directed reaching is important for the activities of daily living. Populations of neurons in the primary motor cortex that project to spinal motor circuits are known to represent the kinematics of reaching movements. We investigated whether repetitive practice of goal-directed reaching movements induces use-dependent plasticity of those kinematic characteristics, in a manner similar to finger movements, as had been shown previously. Transcranial magnetic stimulation (TMS) was used to evoke upper extremity movements while the forearm was resting in a robotic cradle. Plasticity was measured by the change in kinematics of these evoked movements following goal-directed reaching practice. Baseline direction of TMS-evoked arm movements was determined for each subject. Subjects then practiced three blocks of 160 goal-directed reaching movements in a direction opposite to the baseline direction (14 cm reach 180° from baseline direction) against a 75-Nm spring field. Changes in TMS-evoked whole arm movements were assessed after each practice block and after 5 min following the end of practice. Direction and the position of the point of peak velocity of TMS-evoked movements were significantly altered following training and at a 5-min interval following training, while amplitude did not show significant changes. This was accompanied by changes in the motor-evoked potentials (MEPs) of the shoulder and elbow agonist muscles that partly explained the change in direction, mainly by increase in agonist MEP, without significant changes in antagonists. These findings demonstrate that the arm representation accessible by motor cortical stimulation under goes rapid plasticity induced by goal-directed robotic reach training in healthy subjects. PMID:23669007
Full Text Available Increasingly vast research efforts are devoted to the development of materials and processes for solar hydrogen production by light-driven dissociation of water into oxygen and hydrogen. Storage of solar energy in chemical bonds resolves the issues associated with the intermittent nature of sunlight, by decoupling energy generation and consumption. This paper investigates recent advances and prospects in solar hydrogen processes that are reaching market readiness. Future energy scenarios involving solar hydrogen are proposed and a case is made for systems producing hydrogen from water vapor present in air, supported by advanced modeling.
The protocol was designed to engage the user in an assortment of static and dynamic arm matching and opposing tasks. The training incorporates force feedback movements, force feedback positioning, and force matching tasks with same and opposite direction movements. We are able to suggest identification
A survey of 26 Rorschach experts and 19 students of Rorschach use was conducted to help students using the Exner Comprehensive System determine whether to code movement for nouns with definitions that include movement. Experts and students did not reach agreement, but a literature review suggests such nouns should often be coded as movement. (SLD)
Baker, Mariah; Rosenthal, L.; Gaughan, A.; Hopkins, E.
Strawbridge Observatory at Haverford College is home to a undergraduate-led public observing program. Our program holds ~once monthly public events throughout the academic year that take advantage of eyepiece observing on our 16-inch and 12-inch telescopes as well as of the classroom, library, and projection system. These resources allow us to organize a variety of astronomy related activities that are engaging for individuals of all ages: accessible student talks, current film screenings and even arts and crafts for the families who attend with young children. These events aim to spark curiosity in others about scientific discovery and about the remarkable nature of the world in which we live. In addition to exciting local families about astronomy, this program has excited Haverford students from a range of disciplines about both science and education. Being entirely student led means that we are able to take the initiative in planning, coordinating and running all events, fostering an atmosphere of collaboration, experimentation and commitment amongst our volunteers. Additionally, this program is one of the few at Haverford that regularly reaches beyond the campus walls to promote and build relationships with the outside community. In light of this, our program presents a distinctive and enlightening opportunity for student volunteers: we get to use our scientific backgrounds to educate a general audience, while also learning from them about how to communicate and inspire in others the excitement we feel about the subject of astronomy. The work on this project has been supported by NSF AST-1151462.
The creation of the world's largest sandstone cavern, not a small feat! At the bottom, cave-in preventing steel mesh can be seen clinging to the top of the tunnel. The digging of UX-15, the cavern that will house ATLAS, reached the upper ceiling of LEP on October 10th. The breakthrough which took place nearly 100 metres underground occurred precisely on schedule and exactly as planned. But much caution was taken beforehand to make the LEP breakthrough clean and safe. To prevent the possibility of cave-ins in the side tunnels that will eventually be attached to the completed UX-15 cavern, reinforcing steel mesh was fixed into the walls with bolts. Obviously no people were allowed in the LEP tunnels below UX-15 as the breakthrough occurred. The area was completely evacuated and fences were put into place to keep all personnel out. However, while personnel were being kept out of the tunnels below, this has been anything but the case for the work taking place up above. With the creation of the world's largest...
Effects of target location and uncertainty on reaching movements in standing position Los efectos de la ubicación de la diana y la incertidumbre en los movimientos de alcance en la posición vertical Efeitos da localização do alvo e da incerteza em movimentos de alcance na postura ereta
Luiz de França Bahia Loureiro Junior
Full Text Available The effects of target location and uncertainty of target position on reaching movements while standing were investigated. Ten healthy, right-handed adults stood facing a 17'' touchscreen. They were instructed to press with their right index fingertip a push bottom and touch the center of the target displayed on the screen after it was lighted on, moving quickly their arm. The target was shown either ipsi- or contralateral to the right arm and either in a certain or uncertain position. Reaction time (RT, movement time (MT, and radial error (RE were assessed. Results revealed shorter RT (≈ 35 ms and smaller RE (≈ 0.19 cm for certain than for uncertain condition and slightly longer RT (≈ 8 ms and MT (≈ 18 ms for reaches towards the contralateral target. In conclusion, the findings of this study showing the effect of uncertainty of target location as well as target position are also applied to arm reaching in standing position.Los efectos de la ubicación de la diana y la incertidumbre acerca de la posición de la diana en los movimientos de alcance fueron investigados. Diez adultos sanos y diestros estaban frente a una pantalla táctil de 17''. Se les instruyó para presionar un interruptor con el dedo índice derecho y tocar el centro de la diana que aparece en la pantalla después de haber sido iluminado, moviéndo rápidamente su miembro superior. La diana fue mostrada ya sea ipsi o contralateralmente y los participantes tenían o no certidumbre sobre la posición de la misma. El tiempo de reacción (TR, el tiempo de movimiento (TM, y el error radial (ER fueron evaluados. Los resultados revelaron ser más cortos TR (≈ 35 ms y RE menor (≈ 0,19cm en la condición de certeza y mayores TR (≈ 8 ms y TM (≈ 18 ms en los movimientos hacia la meta contralateral. En conclusión, los hallazgos de este estudio que muestra los efectos de la incertidumbre de la ubicación de la diana, así como la posición de la diana se aplican también a
Herbort, Oliver; Ognibene, Dimitri; Butz, Martin V.; Baldassarre, Gianluca
We present a developmental neural network model of motor learning and control, called RL SURE REACH. In a childhood phase, a motor controller for goal directed reaching movements with a redundant arm develops unsupervised. In subsequent task-specific learning phases, the neural network acquires goal-modulation skills. These skills enable RL SURE REACH to master a task that was used in a psychological experiment by Trommersh ? user, Maloney, and Landy (2003). This task required participants to...
Anglada i Escalona, J. Ramon
Justificación: La cirugía bimanual (MICS) de la catarata tiene como características básicas la separación de funciones y el concepto de mínima agresión. Se explican las claves para la transición quirúrgica desde la técnica coaxial convencional. Metodología: Estudio prospectivo y comparativo de 222 procedimientos quirúrgicos con un año de seguimiento. Para cada una de las técnicas se seleccionaron diferentes grupos, tal como se especifica: 3 grupos de cirugía coaxial, con incisiones de 3.2...
The author describes the development of protest movements in postwar Germay and outlines two essential overlapping 'flow cycles'. The first of these was characterised by the restaurative postwar years. It culminated and ended in the students' revolt. This revolt is at the same time the start of a second cycle of protest which encompasses all subsequent individual movement and is initated by an economic, political and sociocultural procrastination of modernisation. This cycle culminates in the late 70s and early 80s and clearly lost momentum over the last few years. The follwoing phases and themes are described profoundly: against restauration and armament in the 1950; the revolutionary impatience of the students' movement, politisation of everyday life by the womens' movement and citizens' action groups, antinuclear- and ecological movement, differentiation and stabilisation of the movement in the 70s and 80s; break-up and continuity in the German protest behaviour. The paper contains a detailed chronicle of protest activities since 1945. (orig.)
Gao, Z G; Sun, S Q; Goonetilleke, R S; Chow, D H K
Manual load carriage continues to be a major contributor of musculoskeletal injury. This study investigates the physiological and subjective effects of an on-hip load-carrying belt (HLCB) during bimanual anterior load carriage. Fifteen healthy male participants walked on a level ground treadmill at 4.5 km/h for 5 min carrying 5, 10 and 15 kg loads with hands and arms in front of the body, with and without using the HLCB (WD and ND). Heart rate, normalized oxygen uptake, minute ventilation and, central and peripheral ratings of perceived exertion were the dependent variables. The mean heart rate, normalized oxygen uptake, minute ventilation and peripheral rating of perceived exertion increased significantly with load under both WD and ND conditions. At a load of 15 kg, the mean heart rate, normalized oxygen uptake, minute ventilation and peripheral rating of perceived exertion were significantly lower by 6.6%, 8.0%, 11.8% and 13.9% respectively in WD condition when compared to the ND condition. There was no significant difference between WD and ND conditions with 5 or 10 kg load. It can be concluded that the HLCB could reduce a person's physiological and peripheral perceptual responses when walking on a level ground treadmill at 4.5 km/h with a load of 15 kg. Using a HLCB or similar device is therefore recommended for bimanual anterior load carriage for loads of 15 kg or probably larger. PMID:26995043
Balasubramanian, Sivakumar; Melendez-Calderon, Alejandro; Roby-Brami, Agnes; Burdet, Etienne
Quantitative measures of smoothness play an important role in the assessment of sensorimotor impairment and motor learning. Traditionally, movement smoothness has been computed mainly for discrete movements, in particular arm, reaching and circle drawing, using kinematic data. There are currently very few studies investigating smoothness of rhythmic movements, and there is no systematic way of analysing the smoothness of such movements. There is also very little work on the smoothness of othe...
Modified constraint-induced movement therapy or bimanual occupational therapy following injection of Botulinum toxin-A to improve bimanual performance in young children with hemiplegic cerebral palsy: a randomised controlled trial methods paper
Imms Christine; Hoare Brian J; Rawicki Hyam; Carey Leeanne
Abstract Background Use of Botulinum toxin-A (BoNT-A) for treatment of upper limb spasticity in children with cerebral palsy has become routine clinical practice in many paediatric treatment centres worldwide. There is now high-level evidence that upper limb BoNT-A injection, in combination with occupational therapy, improves outcomes in children with cerebral palsy at both the body function/structure and activity level domains of the International Classification of Functioning, Disability an...
Caminiti, R; Ferraina, S; Mayer, A B
Recent studies of visually guided reaching in monkeys support the hypothesis that the visuomotor transformations underlying arm movements to spatial targets involve a parallel mechanism that simultaneously engages functionally related frontal and parietal areas linked by reciprocal cortico-cortical connections. The neurons in these areas possess similar combinations of response properties. The multimodal combinatorial properties of these neurons and the gradient architecture of the parietofrontal network emerge as a potential substrate to link the different sensory and motor signals that arise during reaching behavior into common hybrid reference frames. This convergent combinatorial process is evident at early stages of visual information processing in the occipito-parietal cortex, suggesting the existence of re-entrant motor influences on cortical areas once believed to have only visual functions. PMID:9914239
levels than those related to building, and this exploration is a special challenge and competence implicit artistic development work. The project Mixed Movements generates drawing-material, not primary as representation, but as a performance-based media, making the body being-in-the-media felt and appear......Mixed Movements is a research project engaged in performance-based architectural drawing. Architectonic implementation questions relations between the human body and a body of architecture by the different ways we handle drawing materials. A drawing may explore architectonic problems at other...
note onsets and short interaction times between player and instrument do not allow for much adjustment once a stroke is initiated. The paper surveys research that shows a close relationship between movement and sound production, and how playing conditions such as tempo and the rebound after impact......Like all music performance, percussion playing requires high control over timing and sound properties. Specific to percussionists, however, is the need to adjust the movement to different instruments with varying physical properties and tactile feedback to the player. Furthermore, the well defined...
Meguerditchian, Adrien; Vauclair, Jacques; Hopkins, William D
Within the evolutionary framework about the origin of human handedness and hemispheric specialization for language, the question of expression of population-level manual biases in nonhuman primates and their potential continuities with humans remains controversial. Nevertheless, there is a growing body of evidence showing consistent population-level handedness particularly for complex manual behaviors in both monkeys and apes. In the present article, within a large comparative approach among primates, we will review our contribution to the field and the handedness literature related to two particular sophisticated manual behaviors regarding their potential and specific implications for the origins of hemispheric specialization in humans: bimanual coordinated actions and gestural communication. Whereas bimanual coordinated actions seem to elicit predominance of left-handedness in arboreal primates and of right-handedness in terrestrial primates, all handedness studies that have investigated gestural communication in several primate species have reported stronger degree of population-level right-handedness compared to noncommunicative actions. Communicative gestures and bimanual actions seem to affect differently manual asymmetries in both human and nonhuman primates and to be related to different lateralized brain substrates. We will discuss (1) how the data of hand preferences for bimanual coordinated actions highlight the role of ecological factors in the evolution of handedness and provide additional support the postural origin theory of handedness proposed by MacNeilage [MacNeilage . Present status of the postural origins theory. In W. D. Hopkins (Ed.), The evolution of hemispheric specialization in primates (pp. 59-91). London: Elsevier/Academic Press] and (2) the hypothesis that the emergence of gestural communication might have affected lateralization in our ancestor and may constitute the precursors of the hemispheric specialization for language. PMID
Hopkins, William D.; Hook, Michelle; Braccini, Stephanie; Steven J. Schapiro
The purpose of this study was to evaluate the reliability of previously published findings on hand preferences in chimpanzees by evaluating hand use in a second colony of captive chimpanzees. We assessed hand preferences for a coordinated bimanual task in 116 chimpanzees (Pan troglodytes) at the University of Texas M. D. Anderson Cancer Center and compared them to previously published findings in captive chimpanzees at the Yerkes National Primate Research Center. The new sample showed signifi...
Kawashima, Noritaka; Mita, Tomoki
A phantom limb is the sensation that an amputated limb is still attached to the body and is moving together with other body parts. Phantom limb phenomenon is often described on the basis of the patient's subjective sense, for example as represented using a visual analog scale (VAS). The aim of this study was to propose a novel quantification method for behavioral aspect of phantom limb by psychophysics. Twelve unilateral forearm amputees were asked to perform phantom wrist motion with various motion frequencies (60, 80, 100, 120, 140, 160, 180, 200, 220, 240% of preferred speed). The attainment of phantom limb motion in each session was rated by the VAS ranging from 0 (hard) to 10 (easy). The relationship between the VAS and motion frequency was mathematically fitted by quadric function, and the value of shift and the degree of steepness were obtained as evaluation variables for the phantom limb movement. In order to test whether the proposed method can reasonably quantify the characteristics of phantom limb motion, we compared the variables among three different phantom limb movement conditions: (1) unilateral (phantom only), (2) bimanual, and (3) bimanual wrist movement with mirror reflection-induced visual feedback (MVF). While VAS rating showed a larger extent of inter- and intra-subject variability, the relationship of the VAS in response to motion frequency could be fitted by quadric curve, and the obtained parameters based on quadric function well characterize task-dependent changes in phantom limb movement. The present results suggest the potential usefulness of psychophysical evaluation as a validate assessment tool of phantom limb condition. PMID:27227973
This thesis describes the measurement of brain-tissue functions in patients with movement disorders using positron emission tomography (PET). This scanning technique is a method for direct in vivo quantitation of the regional tissue content of positron emitting radionuclides in brain (or other organs) in an essentially non-invasive way. Ch. 2 outlines some general features of PET and describes the scanner which has been used for the studies in this thesis. Also the tracer methodology, as applied to data investigations of movement disorders, are discussed. Ch. 3 contains the results of the PET investigations which were performed in the study of movement disorders. The results are presented in the form of 12 papers. The main goals of these studies were the understanding of the pathophysiology of Parkinson's disease, Huntington's chorea, Steele-Richardson-Olzewski syndrome and special case reports. Ch. 4 summarizes the results of these publications and Ch. 5 concludes the main part of this thesis with a general discussion of movement disorders in relation to PET investigations. 697 refs.; 60 figs.; 31 tabs
Pedersen, Inge Nygaard
This chapter/article describes the historical development of the disciplin Psychodynamic Movement. The importance of this disciplin for self-experience and for training in developing a therapist identy for the music therapy students are emphasized. Prototypeexercises developed and simplified...
Full Text Available In 1984 Christopher Cordner offered a critical view on theories of graceful movement in sport developed by Ng. G. Wulk, David Best and Joseph Kupfer. In 2001 Paul Davis criticized his view. Cordner responded, rejecting all the criticism. More than a century before, Herbert Spencer and Jean-Marie Guyau had a similar controversy over grace. Both exchanges of opinion involve three positions: that grace is the most efficient movement and therefore something quantitative and measurable; that grace is expression of the wholeness of person and the world; and that grace is something which neither science nor philosophy can explain. To clarify these conflicting issues, this article proposes to examine the history of the notion which goes back to the Latin gratia and has root in the Ancient Greek charis, and to apply the concepts of cultural anchor and thin coherence, following John R. Searle’s explanation that we produce epistemically objective accounts of ontologically subjective reality.
Cohn, J. V.; DiZio, P.; Lackner, J. R.
Subjects who are in an enclosed chamber rotating at constant velocity feel physically stationary but make errors when pointing to targets. Reaching paths and endpoints are deviated in the direction of the transient inertial Coriolis forces generated by their arm movements. By contrast, reaching movements made during natural, voluntary torso rotation seem to be accurate, and subjects are unaware of the Coriolis forces generated by their movements. This pattern suggests that the motor plan for reaching movements uses a representation of body motion to prepare compensations for impending self-generated accelerative loads on the arm. If so, stationary subjects who are experiencing illusory self-rotation should make reaching errors when pointing to a target. These errors should be in the direction opposite the Coriolis accelerations their arm movements would generate if they were actually rotating. To determine whether such compensations exist, we had subjects in four experiments make visually open-loop reaches to targets while they were experiencing compelling illusory self-rotation and displacement induced by rotation of a complex, natural visual scene. The paths and endpoints of their initial reaching movements were significantly displaced leftward during counterclockwise illusory rotary displacement and rightward during clockwise illusory self-displacement. Subjects reached in a curvilinear path to the wrong place. These reaching errors were opposite in direction to the Coriolis forces that would have been generated by their arm movements during actual torso rotation. The magnitude of path curvature and endpoint errors increased as the speed of illusory self-rotation increased. In successive reaches, movement paths became straighter and endpoints more accurate despite the absence of visual error feedback or tactile feedback about target location. When subjects were again presented a stationary scene, their initial reaches were indistinguishable from pre
This SpringerBrief discusses the characteristics of spatiotemporal movement data, including uncertainty and scale. It investigates three core aspects of Computational Movement Analysis: Conceptual modeling of movement and movement spaces, spatiotemporal analysis methods aiming at a better understanding of movement processes (with a focus on data mining for movement patterns), and using decentralized spatial computing methods in movement analysis. The author presents Computational Movement Analysis as an interdisciplinary umbrella for analyzing movement processes with methods from a range of fi
Yousif, Nada; Greenwood, Richard; Rothwell, John C.; Diedrichsen, Jörn
How does the motor system choose the speed for any given movement? Many current models assume a process that finds the optimal balance between the costs of moving fast and the rewards of achieving the goal. Here, we show that such models also need to take into account a prior representation of preferred movement speed, which can be changed by prolonged practice. In a time-constrained reaching task, human participants made 25-cm reaching movements within 300, 500, 700, or 900 ms. They were then trained for 3 days to execute the movement at either the slowest (900-ms) or fastest (300-ms) speed. When retested on the 4th day, movements executed under all four time constraints were biased toward the speed of the trained movement. In addition, trial-to-trial variation in speed of the trained movement was significantly reduced. These findings are indicative of a use-dependent mechanism that biases the selection of speed. Reduced speed variability was also associated with reduced errors in movement amplitude for the fast training group, which generalized nearly fully to a new movement direction. In contrast, changes in perpendicular error were specific to the trained direction. In sum, our results suggest the existence of a relatively stable but modifiable prior of preferred movement speed that influences the choice of movement speed under a range of task constraints. PMID:24133220
Andreu-Perez, Javier; Leff, Daniel Richard; Shetty, Kunal; Darzi, Ara; Yang, Guang-Zhong
Objective metrics of technical performance (e.g., dexterity, time, and path length) are insufficient to fully characterize operator skill level, which may be encoded deep within neural function. Unlike reports that capture plasticity across days or weeks, this articles studies long-term plasticity in functional connectivity that occurs over years of professional task practice. Optical neuroimaging data are acquired from professional surgeons of varying experience on a complex bimanual coordination task with the aim of investigating learning-related disparity in frontal lobe functional connectivity that arises as a consequence of motor skill level. The results suggest that prefrontal and premotor seed connectivity is more critical during naïve versus expert performance. Given learning-related differences in connectivity, a least-squares support vector machine with a radial basis function kernel is employed to evaluate skill level using connectivity data. The results demonstrate discrimination of operator skill level with accuracy ≥0.82 and Multiclass Matthew's Correlation Coefficient ≥0.70. Furthermore, these indices are improved when local (i.e., within-region) rather than inter-regional (i.e., between-region) frontal connectivity is considered (p = 0.002). The results suggest that it is possible to classify operator skill level with good accuracy from functional connectivity data, upon which objective assessment and neurofeedback may be used to improve operator performance during technical skill training. PMID:26899241
Rai Harminder K
Full Text Available Abstract Background The prerequisites for a good capsulorhexis include a deep, well maintained anterior chamber, globe stabilization and globe manipulation. This helps to achieve a capsulorhexis of optimal size, shape and obtain the best possible position for a red glow under retroillumination. We report the use of irrigation handpiece of bimanual irrigation aspiration system to stabilize the globe, maintain a deep anterior chamber and manipulate the globe to a position of optimal red reflex during needle capsulorhexis in phacoemulsification. Methods Two side ports are made with 20 G MVR 'V' lance knife (Alcon, USA. The irrigation handpiece with irrigation on is introduced into the anterior chamber through one side port and the 26-G cystitome (made from 26-G needle is introduced through the other. The capsolurhexis is completed with the needle. Results Needle capsulorhexis with this technique was used in 30 cases of uncomplicated immature senile cataracts. 10 cases were done under peribulbar anaesthesia and 20 under topical anaesthesia. A complete capsulorhexis was achieved in all cases. Conclusion The irrigating handpiece maintains deep anterior chamber, stabilizes the globe, facilitates pupillary dilatation, and helps in maintaining the eye in the position with optimal red reflex during needle capsulorhexis. This technique is a safe and effective way to perform needle capsulorhexis.
ABOUT THE BOOK Halo Reach is the latest installment, and goes back to Halo's roots in more ways than one. Set around one of the most frequently referenced events in the Haloverse-The Fall of Reach-Reach puts you in the shoes of Noble 6, an unnamed Spartan, fighting a doomed battle to save the planet. Dual-wielding's gone, health is back, and equipment now takes the form of different "classes," with different weapon loadouts and special abilities (such as sprinting, cloaking, or flight). If you're reading this guide, you're either new to the Halo franchise and looking to get a leg up on all
Full Text Available Abstract Background How the central nervous system (CNS organizes the joint dynamics for multi-joint movement is a complex problem, because of the passive interaction among segmental movements. Previous studies have demonstrated that the CNS predictively compensates for interaction torque (INT which is arising from the movement of the adjacent joints. However, most of these studies have mainly examined quick movements, presumably because the current belief is that the effects of INT are not significant at slow speeds. The functional contribution of INT for multijoint movements performed in various speeds is still unclear. The purpose of this study was to examine the contribution of INT to a planer reaching in a wide range of motion speeds for healthy subjects. Methods Subjects performed reaching movements toward five targets under three different speed conditions. Joint position data were recorded using a 3-D motion analysis device (50 Hz. Torque components, muscle torque (MUS, interaction torque (INT, gravity torque (G, and net torque (NET were calculated by solving the dynamic equations for the shoulder and elbow. NET at a joint which produces the joint kinematics will be an algebraic sum of torque components; NET = MUS - G - INT. Dynamic muscle torque (DMUS = MUS-G was also calculated. Contributions of INT impulse and DMUS impulse to NET impulse were examined. Results The relative contribution of INT to NET was not dependent on speed for both joints at every target. INT was additive (same direction to DMUS at the shoulder joint, while in the elbow DMUS counteracted (opposed to INT. The trajectory of reach was linear and two-joint movements were coordinated with a specific combination at each target, regardless of motion speed. However, DMUS at the elbow was opposed to the direction of elbow movement, and its magnitude varied from trial to trial in order to compensate for the variability of INT. Conclusion Interaction torque was important at
This review covers the following areas: (1) the physics of burning plasmas, (2) plasma physics requirements for reaching ignition, (3) design studies for ignition devices, and (4) prospects for an ignition project
@@ China's second lunar probe, Chang'e-2, has reached an orbit 1.5 million kilometers from Earth for an additional mission of deep space exploration, the State Administration for Science, Technology and Industry for National Defense announced.
Gresik, G. W. L.; Siebe, S.; Drewello, R.
The goal of RECORDS (Reaching Recording Data Technologies) is the digital capturing of buildings and cultural heritage objects in hard-to-reach areas and the combination of data. It is achieved by using a modified crane from film industry, which is able to carry different measuring systems. The low-vibration measurement should be guaranteed by a gyroscopic controlled advice that has been , developed for the project. The data were achieved by using digital photography, UV-fluorescence...
Mitchell, Lauren Coleen
As the body moves through space ephemeral lines of movement are created. These lines of movement are influenced by body tendencies. We learn from the body by watching the path and patterning of movement. From the study of the movement of the body, theories of spacial movement were developed. The goal of my project is to draw from spacial movement theory to create an architectural expression that motivates movement of the body on my site and through my building. The focus of my thesis is ...
AIM: We compared bimanual microincision cataract surgery (MICS) and standard coaxial phacoemulsification (CAP) in terms of uncorrected visual acuity (UCVA) recorded 1 h and 2 weeks postoperatively. METHODS: This was a prospective, nonrandomised comparative study. All MICS procedures were performed by one surgeon (MGM), and all CAP procedures were performed by another surgeon (SB). Eyes with visually consequential ocular morbidity were excluded. The primary outcome measure was UCVA recorded 1 h postoperatively. RESULTS: One hundred eyes underwent MICS and CAP (50 eyes in each group). The treatment groups did not differ significantly in terms of preoperative mean best corrected visual acuity (6\\/24 +\\/- 4.3 lines and 6\\/20 +\\/- 4.4 lines in the MICS and the CAP groups, respectively; P = 0.65). Also, there was no significant difference in terms of postoperative UCVA at 1 h or at 2 weeks (mean +\\/- standard deviation UCVA 1 h postoperatively: MICS: 6\\/36 +\\/- 5.7 lines; CAP: 6\\/30 +\\/- 4.7 lines; P = 0.80; UCVA 2 weeks postoperatively: MICS: 6\\/10 +\\/- 1.9 lines; CAP: 6\\/10 +\\/- 2.2 lines; P = 0.90). However, nine eyes (18%) and one eye (2%) achieved a UCVA of C6\\/12 at 1 h following MICS and CAP, respectively, and this difference was statistically significant (P = 0.02). CONCLUSION: Mean UCVA at 1 h and at 2 weeks following cataract surgery was not significantly different between eyes undergoing MICS and CAP. However, a greater proportion of patients achieved a UCVA of C6\\/12 following MICS when compared with CAP.
Stoessl, A Jon; Mckeown, Martin J
Movement disorders can be hypokinetic (e.g., parkinsonism), hyperkinetic, or dystonic in nature and commonly arise from altered function in nuclei of the basal ganglia or their connections. As obvious structural changes are often limited, standard imaging plays less of a role than in other neurologic disorders. However, structural imaging is indicated where clinical presentation is atypical, particularly if the disorder is abrupt in onset or remains strictly unilateral. More recent advances in magnetic resonance imaging (MRI) may allow for differentiation between Parkinson's disease and atypical forms of parkinsonism. Functional imaging can assess regional cerebral blood flow (functional MRI (fMRI), positron emission tomography (PET), or single-photon emission computed tomography (SPECT)), cerebral glucose metabolism (PET), neurochemical and neuroreceptor status (PET and SPECT), and pathologic processes such as inflammation or abnormal protein deposition (PET) (Table 49.1). Cerebral blood flow can be assessed at rest, during the performance of motor or cognitive tasks, or in response to a variety of stimuli. In appropriate situations, the correct imaging modality and/or combination of modalities can be used to detect early disease or even preclinical disease, and to monitor disease progression and the effects of disease-modifying interventions. Various approaches are reviewed here. PMID:27430452
Full Text Available This article acknowledges the need for Church Planting Movements among the unreached peoples of India. Of particular concern to this study is the application of Church Planting Movement strategy to forward caste Hindus of India. It is shown that evangelizing households (family or �oikos� evangelism is a New Testament strategy and the most appropriate strategy for reaching forward caste Hindus. It is concluded that Christian disciples remaining within Hindu culture and familial systems hold the potential for the most indigenous approach to evangelizing forward caste Hindus.
Gresik, G. W. L.; Siebe, S.; Drewello, R.
The goal of RECORDS (Reaching Recording Data Technologies) is the digital capturing of buildings and cultural heritage objects in hard-to-reach areas and the combination of data. It is achieved by using a modified crane from film industry, which is able to carry different measuring systems. The low-vibration measurement should be guaranteed by a gyroscopic controlled advice that has been , developed for the project. The data were achieved by using digital photography, UV-fluorescence photography, infrared reflectography, infrared thermography and shearography. Also a terrestrial 3D laser scanner and a light stripe topography scanner have been used The combination of the recorded data should ensure a complementary analysis of monuments and buildings.
Diedrichsen, Jörn; Hashambhoy, Yasmin; Rane, Tushar; Shadmehr, Reza
Reach errors may be broadly classified into errors arising from unpredictable changes in target location, called target errors, and errors arising from miscalibration of internal models, called execution errors. Execution errors may be caused by miscalibration of dynamics (e.g.. when a force field alters limb dynamics) or by miscalibration of kinematics (e.g., when prisms alter visual feedback). While all types of errors lead to similar online corrections, we found that the motor system showe...
de Haan, J.; W.P. Knulst
Original title: Het bereik van de kunsten. The reach of the arts (Het bereik van de kunsten) is the fourth study in a series which periodically analyses the status of cultural participation, reading and use of other media. The series, Support for culture (Het culturele draagvlak) is sponsored by the Dutch Ministry of Education, Culture and Science. This study investigates the interest in the performing and visual arts. Most attention is devoted to visits to theatres, concert halls and museums...
Burnod, Y; Baraduc, P; Battaglia-Mayer, A; Guigon, E; Koechlin, E; Ferraina, S; Lacquaniti, F; Caminiti, R
In the last few years, anatomical and physiological studies have provided new insights into the organization of the parieto-frontal network underlying visually guided arm-reaching movements in at least three domains. (1) Network architecture. It has been shown that the different classes of neurons encoding information relevant to reaching are not confined within individual cortical areas, but are common to different areas, which are generally linked by reciprocal association connections. (2) Representation of information. There is evidence suggesting that reach-related populations of neurons do not encode relevant parameters within pure sensory or motor "reference frames", but rather combine them within hybrid dimensions. (3) Visuomotor transformation. It has been proposed that the computation of motor commands for reaching occurs as a simultaneous recruitment of discrete populations of neurons sharing similar properties in different cortical areas, rather than as a serial process from vision to movement, engaging different areas at different times. The goal of this paper was to link experimental (neurophysiological and neuroanatomical) and computational aspects within an integrated framework to illustrate how different neuronal populations in the parieto-frontal network operate a collective and distributed computation for reaching. In this framework, all dynamic (tuning, combinatorial, computational) properties of units are determined by their location relative to three main functional axes of the network, the visual-to-somatic, position-direction, and sensory-motor axis. The visual-to-somatic axis is defined by gradients of activity symmetrical to the central sulcus and distributed over both frontal and parietal cortices. At least four sets of reach-related signals (retinal, gaze, arm position/movement direction, muscle output) are represented along this axis. This architecture defines informational domains where neurons combine different inputs. The position
Full Text Available The article discusses the ways of getting library activities closer to the individuals or groups of users who have difficulties to or cannot visit the library themselves. The author presents the services offered by the Maribor Public Library and discusses how one of the basic human rights – the right to the access of cultural goods, knowledge and information - is exercised also through library activities. By enabling access to library material and information, public libraries help to fulfill basic human rights and thus raise the quality of living in a social environment. The following forms of library activities are presented in the article: »distance library« – borrowing books at home, in hospital, station for the bibliobus for disabled users, »mobile collections« in the institutions where users, due to their age or illness, have difficulties in accessing or even cannot reach library materials and information by themselves.
Wei Liu, PhD
Full Text Available After stroke, movement patterns of the upper limb (UL during functional arm reaching change to accommodate altered constraints. These compensatory movement control strategies do not, however, have a one-to-one mapping with posttraining outcomes. In this study, we quantify arm movement control strategies in unilateral and bilateral reaching tasks using induced position analysis. In addition, we assess how those strategies are associated with UL residual impairments and with functional improvement after a specific bilateral arm training intervention. Twelve individuals with chronic stroke were measured while reaching to a box as part of their pre- and posttesting assessments. Other measurements included the Fugl-Meyer Upper Extremity Assessment (FM, Modified Wolf Motor Function Test (WT, and the University of Maryland Arm Questionnaire for Stroke (UMAQS. We identified arm control strategies that did not differ between unilateral and bilateral tasks but did differ by FM impairment level and by predicted gains in WT but not UMAQS. Increased shoulder relative to elbow moment contribution was associated with less impairment and greater gains of speed in functional tasks. These results suggest that one goal of training to achieve better outcomes may be to decrease the abnormal coupling of the shoulder and elbow.
Full Text Available According to action-centered models of attention, the patterns of distractor interference that emerge in selective reaching tasks are related to the time and effort required to resolve a race for activation between competing target and non-target response producing processes. Previous studies have only used unimanual aiming tasks and, as such, only examined the effects of competition that occurs within a limb. The results of studies using unimanual aiming movements often reveal an "ipsilateral effect"--distractors on the same side of space as the effector cause greater interference than distractors on the opposite side of space. The cost of the competition when response selection is between the limbs has yet to be addressed. Participants in the present study executed reaching movements to 1 of 4 (2 left, 2 right possible target locations with and without a distractor. Participants made ipsilateral reaches (left hand to left targets, right hand to right targets. In contrast to studies using unimanual aiming movements, a "contralateral effect" was observed; distractors affording responses for the other hand (in contralateral space caused more interference than distractors affording responses for the same hand. The findings from the present research demonstrate that when certain portions of response planning must be resolved prior to response initiation, distractors that code for that dimension cause the greatest interference.
New challenges for regulators are emerging about a specific assessment and appropriate management of the potential risks of nanomaterials. In the framework of European legislation on chemicals, Regulation (EC) No. 1907/2006 REACH aims to ensure the safety of human health and the environment through the collection of information on the physico-chemical characteristics of the substances and on their profile (eco) toxicological and the identification of appropriate risk management linked to 'exposure to these substances without impeding scientific progress and the competitiveness of industry. In order to cover the current shortage of information on the safety of nanomaterials and tackle the acknowledged legal vacuum, are being a rich activities, carried out both by regulators both by stake holders, and discussions on the proposals for adapting the European regulatory framework for chemicals . The European Commission is geared to strengthen the REACH Regulation by means of updates of its annexes. The importance of responding to the regulatory requirements has highlighted the need for cooperation between European organizations, scientists and industries to promote and ensure the safe use of nanomaterials.
YANG Jingzhou(杨景周); ZHANG Yunqing(张云清); CHEN Liping(陈立平); ABDEL-MALEK Karim
Significant attention in recent years has been given to obtain a better understanding of human joint ranges, measurement, and functionality, especially in conjunction with commands issued by the central nervous system. While researchers have studied motor commands needed to drive a limb to follow a path trajectory, various computer algorithms have been reported that provide adequate analysis of limb modeling and motion. This paper uses a rigorous mathematical formulation to model human limbs, understand their reach envelope, delineate barriers therein where a trajectory becomes difficult to control, and help visualize these barriers. Workspaces of a typical forearm with 9 degrees of freedom, a typical finger modeled as a 4- degree-of-freedom system, and a lower extremity with 4 degrees of freedom are discussed. The results show that using the proposed formulation, joint limits play an important role in distinguishing the barriers.
As the nuclear power industry enters the 1980s, uranium enrichment supply can no longer be considered one of the critical problem areas of the nuclear fuel cycle. It has become an industrial and commercial activity which has reached a high degree of maturity. Three main aspects of this maturity are discussed: 1. the availability of enrichment services from several facilities with very diverse ownership; 2. the involvement of private industry, especially in Europe, and the application of normal commercial rules to enrichment contracts; 3. the ability of the enrichment industry to cope with recent setbacks in the advancement of nuclear power programmes whilst carrying out an active research and development programme that will help to ensure its future technical and economic viability. (U.K.)
McCombe Waller, Sandy; Yang, Chieh-Ling; Magder, Laurence; Yungher, Don; Gray, Vicki; Rogers, Mark W
Movement preparation of both anticipatory postural adjustments (APAs) and goal directed movement during a standing reaching task in adults with chronic hemiparesis and healthy controls was investigated. Using a simple reaction time paradigm, while standing on two separate force platforms, subjects received a warning light cue to "get ready to reach" followed 2.5s later by an imperative light cue to "reach as quickly as possible" with the paretic arm (matched arm for controls) to touch a target in front of them for a total of 90 trials. In 30 of the reaching trials a loud acoustic stimulus (LAS) of 123 dB was randomly - -200, or 0ms relative to the "go" cue. APA (postural) responses were characterized by the onset and maximal posterior displacement of center of pressure (CoP) and onset/offset of electromyography (EMG) from tibialis anterior (TA), soleus (SOL), while reach was characterized by onset and maximal forward displacement of the reach hand and onset of the anterior (AD), biceps brachii (BB) and middle deltoid (MD). Subjects with stroke, demonstrated a marked reduction in the occurrence of the StartReact responses for both APA and forward reach at all LAS time points indicating movement preparation dysfunction. Movement execution during a cued reach showed significant delays in APA and reach onsets, significant reduction in the magnitude of APA (posterior CoP displacement) and reach excursion, and an increased latency between the APA and reach compared to controls. EMG activation patterns for the TA and SOL demonstrated co contraction compared to the temporally sequenced pattern of control subjects. When LAS was provided at the "go" there were earlier but not significant differences in APA onset latency compared to reaching without LAS and significant delays in reach onset latency when compared to control subjects with or without LAS. An early burst of EMG in biceps brachii muscles with a further delay of the reach onset compared to reaching without LAS may
Zheng, Guoxing; Mühlenbernd, Holger; Kenney, Mitchell; Li, Guixin; Zentgraf, Thomas; Zhang, Shuang
Surfaces covered by ultrathin plasmonic structures--so-called metasurfaces--have recently been shown to be capable of completely controlling the phase of light, representing a new paradigm for the design of innovative optical elements such as ultrathin flat lenses, directional couplers for surface plasmon polaritons and wave plate vortex beam generation. Among the various types of metasurfaces, geometric metasurfaces, which consist of an array of plasmonic nanorods with spatially varying orientations, have shown superior phase control due to the geometric nature of their phase profile. Metasurfaces have recently been used to make computer-generated holograms, but the hologram efficiency remained too low at visible wavelengths for practical purposes. Here, we report the design and realization of a geometric metasurface hologram reaching diffraction efficiencies of 80% at 825 nm and a broad bandwidth between 630 nm and 1,050 nm. The 16-level-phase computer-generated hologram demonstrated here combines the advantages of a geometric metasurface for the superior control of the phase profile and of reflectarrays for achieving high polarization conversion efficiency. Specifically, the design of the hologram integrates a ground metal plane with a geometric metasurface that enhances the conversion efficiency between the two circular polarization states, leading to high diffraction efficiency without complicating the fabrication process. Because of these advantages, our strategy could be viable for various practical holographic applications. PMID:25705870
Zheng, Guoxing; Mühlenbernd, Holger; Kenney, Mitchell; Li, Guixin; Zentgraf, Thomas; Zhang, Shuang
Surfaces covered by ultrathin plasmonic structures—so-called metasurfaces—have recently been shown to be capable of completely controlling the phase of light, representing a new paradigm for the design of innovative optical elements such as ultrathin flat lenses, directional couplers for surface plasmon polaritons and wave plate vortex beam generation. Among the various types of metasurfaces, geometric metasurfaces, which consist of an array of plasmonic nanorods with spatially varying orientations, have shown superior phase control due to the geometric nature of their phase profile. Metasurfaces have recently been used to make computer-generated holograms, but the hologram efficiency remained too low at visible wavelengths for practical purposes. Here, we report the design and realization of a geometric metasurface hologram reaching diffraction efficiencies of 80% at 825 nm and a broad bandwidth between 630 nm and 1,050 nm. The 16-level-phase computer-generated hologram demonstrated here combines the advantages of a geometric metasurface for the superior control of the phase profile and of reflectarrays for achieving high polarization conversion efficiency. Specifically, the design of the hologram integrates a ground metal plane with a geometric metasurface that enhances the conversion efficiency between the two circular polarization states, leading to high diffraction efficiency without complicating the fabrication process. Because of these advantages, our strategy could be viable for various practical holographic applications.
Kaneko, Miki; Yamashita, Yushiro; Inomoto, Osamu; Iramina, Keiji
Soft neurological signs (SNS) are evident in the motor performance of children and disappear as the child grows up. Therefore SNS are used as criteria for evaluating age-appropriate development of neurological function. The aim of this study was to quantify SNS during arm movement in childhood. In this study, we focused on pronation and supination, which are arm movements included in the SNS examination. Two hundred and twenty-three typically developing children aged 4-12 years (107 boys, 116 girls) and 18 adults aged 21-26 years (16 males, two females) participated in the experiment. To quantify SNS during pronation and supination, we calculated several evaluation index scores: bimanual symmetry, compliance, postural stability, motor speed and mirror movement. These index scores were evaluated using data obtained from sensors attached to the participants' hands and elbows. Each score increased as age increased. Results obtained using our system showed developmental changes that were consistent with criteria for SNS. We were able to successfully quantify SNS during pronation and supination. These results indicate that it may be possible to use our system as quantitative criteria for evaluating development of neurological function. PMID:26473867
Full Text Available Soft neurological signs (SNS are evident in the motor performance of children and disappear as the child grows up. Therefore SNS are used as criteria for evaluating age-appropriate development of neurological function. The aim of this study was to quantify SNS during arm movement in childhood. In this study, we focused on pronation and supination, which are arm movements included in the SNS examination. Two hundred and twenty-three typically developing children aged 4–12 years (107 boys, 116 girls and 18 adults aged 21–26 years (16 males, two females participated in the experiment. To quantify SNS during pronation and supination, we calculated several evaluation index scores: bimanual symmetry, compliance, postural stability, motor speed and mirror movement. These index scores were evaluated using data obtained from sensors attached to the participants’ hands and elbows. Each score increased as age increased. Results obtained using our system showed developmental changes that were consistent with criteria for SNS. We were able to successfully quantify SNS during pronation and supination. These results indicate that it may be possible to use our system as quantitative criteria for evaluating development of neurological function.
Herzog, Dennis; Krüger, Volker; Grest, Daniel
A common problem in movement recognition is the recognition of movements of a particular type. E.g. pointing movements are of a particular type but differ in terms of the pointing direction. Arm movements with the goal of reaching out and grasping an object are of a particular type but differ with...
Cao, Jianwei; Khan, Bilal; Hervey, Nathan; Tian, Fenghua; Delgado, Mauricio R.; Clegg, Nancy J.; Smith, Linsley; Roberts, Heather; Tulchin-Francis, Kirsten; Shierk, Angela; Shagman, Laura; MacFarlane, Duncan; Liu, Hanli; Alexandrakis, George
Sensorimotor cortex plasticity induced by constraint-induced movement therapy (CIMT) in six children (10.2±2.1 years old) with hemiplegic cerebral palsy was assessed by functional near-infrared spectroscopy (fNIRS). The activation laterality index and time-to-peak/duration during a finger-tapping task and the resting-state functional connectivity were quantified before, immediately after, and 6 months after CIMT. These fNIRS-based metrics were used to help explain changes in clinical scores of manual performance obtained concurrently with imaging time points. Five age-matched healthy children (9.8±1.3 years old) were also imaged to provide comparative activation metrics for normal controls. Interestingly, the activation time-to-peak/duration for all sensorimotor centers displayed significant normalization immediately after CIMT that persisted 6 months later. In contrast to this improved localized activation response, the laterality index and resting-state connectivity metrics that depended on communication between sensorimotor centers improved immediately after CIMT, but relapsed 6 months later. In addition, for the subjects measured in this work, there was either a trade-off between improving unimanual versus bimanual performance when sensorimotor activation patterns normalized after CIMT, or an improvement occurred in both unimanual and bimanual performance but at the cost of very abnormal plastic changes in sensorimotor activity.
@@ The new European REACH (Registration, Evaluation, Authorization of Chemicals) regulation has come into force. As soon as the REACH white paper was issued, Chinese enterprises started to research the possible impacts of REACH and prepare to cope with them. How then do these Chinese enterprises look at REACH? Following are views of some Chinese enterprises exporting chemical products to the European Union.
Riisgaard Hansen, Thomas; Eriksson, Eva; Lykke-Olesen, Andreas
In this paper we explore the space in which movement based interaction takes place. We have in several projects explored how fixed and mobile cameras can be used in movement based interaction and will shortly describe these projects. Based on our experience with working with movement-based intera......In this paper we explore the space in which movement based interaction takes place. We have in several projects explored how fixed and mobile cameras can be used in movement based interaction and will shortly describe these projects. Based on our experience with working with movement...
Presents an activity that employs movement to enable students to understand concepts related to plate tectonics. Argues that movement brings topics to life in a concrete way and helps children retain knowledge. (DDR)
... t work properly. There are many kinds of eye movement disorders. Two common ones are Strabismus - a disorder ... of the eyes, sometimes called "dancing eyes" Some eye movement disorders are present at birth. Others develop over ...
The article examines the role of social movements in the development of scientific knowledge. Interactions between social movements and science in broad, historical terms are discussed. The relations between the new social movements of the 1960s and 1970s and changes in the contemporary scientific...
ball at a distance of nine miles, and to keep their smooth reflecting surfaces accurate to less than the thickness of a human hair. Once the transporter reached the high plateau it carried the antenna to a concrete pad -- a docking station with connections for power and fiber optics -- and positioned it with an accuracy of a small fraction of an inch. The transporter is guided by a laser steering system and, just like some cars, also has ultrasonic collision detectors. These sensors ensure the safety of the state-of-the-art antennas as the transporter drives them across what will soon be a rather crowded plateau. Ultimately, ALMA will have at least 66 antennas distributed over about 200 pads, spread over distances of up to 11.5 miles and operating as a single, giant telescope. Even when ALMA is fully operational, the transporters will be used to move the antennas between pads to reconfigure the telescope for different kinds of observations. This first ALMA antenna at the high site will soon be joined by others, and the ALMA team looks forward to making their first observations from the Chajnantor plateau. They plan to link three antennas by early 2010, and to make the first scientific observations with ALMA in the second half of 2011. ALMA will help astronomers answer important questions about our cosmic origins. The telescope will observe the Universe using light with millimeter and submillimeter wavelengths, between infrared light and radio waves in the electromagnetic spectrum. Light at these wavelengths comes from some of the coldest, and from some of the most distant objects in the cosmos. These include cold clouds of gas and dust where new stars are being born, or remote galaxies towards the edge of the observable universe. The Universe is relatively unexplored at submillimeter wavelengths, as the telescopes need extremely dry atmospheric conditions, such as those at Chajnantor, and advanced detector technology. The Atacama Large Millimeter/submillimeter Array
California Department of Resources — The Stream Habitat - NCWAP - Reach Summary [ds158] shapefile contains in-stream habitat survey data summarized to the stream reach level. It is a derivative of the...
Cochet, Hélène; Centelles, Laurie; Jover, Marianne; Plachta, Suzy; Vauclair, Jacques
Manual asymmetries emerge very early in development and several researchers have reported a significant right-hand bias in toddlers although this bias fluctuates depending on the nature of the activity being performed. However, little is known about the further development of asymmetries in preschoolers. In this study, patterns of hand preference were assessed in 50 children aged 3-5 years for different activities, including reaching movements, pointing gestures and symbolic gestures. Contrary to what has been reported in children before 3 years of age, we did not observe any difference in the mean handedness indices obtained in each task. Moreover, the asymmetry of reaching was found to correlate with that of pointing gestures, but not with that of symbolic gestures. In relation to the results reported in infants and adults, this study may help deciphering the mechanisms controlling the development of handedness by providing measures of manual asymmetries in an age range that has been so far rather neglected. PMID:25651377
Full Text Available New movement assessment and data analysis methods are developed to quantify human arm motion patterns during physical interaction with robotic devices for rehabilitation. These methods provide metrics for future use in diagnosis, assessment and rehabilitation of subjects with affected arm movements. Specifically, the current study uses existing pattern recognition methods to evaluate the effect of age on performance of a specific motion, reaching to a target by moving the end-effector of a robot (an X-Y table. Differences in the arm motion patterns of younger and older subjects are evaluated using two measures: the principal component analysis similarity factor (SPCA to compare path shape and the number of Fourier modes representing 98% of the path ‘energy’ to compare the smoothness of movement, a particularly important variable for assessment of pathologic movement. Both measures are less sensitive to noise than others previously reported in the literature and preserve information that is often lost through other analysis techniques. Data from the SPCA analysis indicate that age is a significant factor affecting the shapes of target reaching paths, followed by reaching movement type (crossing body midline/not crossing and reaching side (left/right; hand dominance and trial repetition are not significant factors. Data from the Fourier-based analysis likewise indicate that age is a significant factor affecting smoothness of movement, and movements become smoother with increasing trial number in both younger and older subjects, although more rapidly so in younger subjects. These results using the proposed data analysis methods confirm current practice that age-matched subjects should be used for comparison to quantify recovery of arm movement during rehabilitation. The results also highlight the advantages that these methods offer relative to other reported measures.
Whishaw, Ian Q; Karl, Jenni M; Humphrey, Nicholas K
Dual visuomotor channel theory proposes that reaching depends on two neural pathways that extend from visual cortex (V1) to motor cortex via the parietal lobe. The Reach pathway directs the hand to the target's location and the Grasp pathway shapes the hand and digits for purchase. Sighted human participants integrate the Reach and the Grasp, but without vision they dissociate the movements to capitalize on tactile cues. They use a Reach with a relatively open hand to locate the target and then they use touch cues to shape the fingers to Grasp. After a V1 lesion, the rhesus monkey, Helen, learned to make near-normal visual discriminations based on size and brightness but displayed visual agnosia. She also learned to reach for food with her mouth and her hands. The present analysis of film of her reaching behavior shows that she dissociated the Reach and the Grasp, as do unsighted human participants reaching for a food target at a fixed location. Her rapid and direct Reach was made with an open hand and extended fingers to contact the food with the palm whereas her Grasp was initiated after she touched the food. She also visually fixated the target during the Reach and visually disengaged after target contact, as do sighted human participants. In contrast, Helen did integrate the Reach and the Grasp to take food from her mouth, demonstrating that she could integrate the movements using online tactile cues. The finding that extrastriate pathways can direct the hand toward extrinsic target properties (location) but not intrinsic target properties (size and shape) is discussed as a novel addition to dual visuomotor channel theory. PMID:27056084
Suzuki, Keisuke; Miyamoto, Masayuki; Miyamoto, Tomoyuki; Hirata, Koichi
Sleep related movement disorders (SRMD) are characterized by simple, stereotyped movements occur during sleep, with the exception of restless legs syndrome (RLS). RLS has the following essential features; an urge to move the legs usually accompanied by uncomfortable sensation in the legs, improvement of symptoms after movement (non-stereotypical movements, such as walking and stretching, to reduce symptoms), and symptoms occur or worsen during periods of rest and in the evening and night. However, RLS is closely associated with periodic limb movement, which shows typical stererotyped limb movements. In the International Classification of Sleep Disorders, 3rd edition, sleep disturbances or daytime symptoms are prerequiste for a diagnosis of SRMD. We here review diagnosis and treatment of SRMD. PMID:26065126
Full Text Available Involuntary movements of different types are associated with many diseases in children. Movement disorders in adult have been published in different journals, but in children these disorders have been ignored, even in most of the paediatric neurology books. Here is a brief attempt to describe different types of movement disorders and their various names in different diseases. Possible investigations and treatment of the disorders have been described in short.
Review of: Quantitative Analysis of Movement: Measuring and Modeling Population Redistribution in Animals and Plants. Peter Turchin. 1998. Sinauer Associates, Sunderland, MA. 306 pages. $38.95 (paper).
Rakusa, Martin; Hribar, Ales; Koritnik, Blaz; Munih, Marko; Battaglni, Piero Paolo; Belic, Ales; Zidar, Janez
Current experimental methods for the study of reaching in the MRI environment do not exactly mimic actual reaching, due to constrains in movement which are imposed by the MRI machine itself. We tested a haptic robot (HR) as such a tool. Positive results would also be promising for combined use of fMRI and EEG to study reaching. Twenty right-handed subjects performed reaching tasks with their right hand with and without the HR. Reaction time, movement time (MT), accuracy, event-related potentials (ERPs) and event-related desynchronisation/synchronisation (ERD/ERS) were studied. Reaction times and accuracies did not differ significantly between the two tasks, while the MT was significantly longer in HR reaching (959 vs. 447 ms). We identified two positive and two negative ERP peaks across all leads in both tasks. The latencies of the P1 and N2 peaks were significantly longer in HR reaching, while there were no significant differences in the P3 and N4 latencies. ERD/ERS topographies were similar between tasks and similar to other reaching studies. Main difference was in ERS rebound which was observed only in actual reaching. Probable reason was significantly larger MT. We found that reaching with the HR engages similar neural structures as in actual reaching. Although there are some constrains, its use may be superior to other techniques used for reaching studies in the MRI environment, where freedom of movement is limited. PMID:23474640
Dickey, Adam S.; Amit, Yali; Hatsopoulos, Nicholas G.
During a reach, neural activity recorded from motor cortex is typically thought to linearly encode the observed movement. However, it has also been reported that during a double-step reaching paradigm, neural coding of the original movement is replaced by that of the corrective movement. Here, we use neural data recorded from multi-electrode arrays implanted in the motor and premotor cortices of rhesus macaques to directly compare these two hypotheses. We show that while a majority of neurons display linear encoding of movement during a double-step, a minority display a dramatic drop in firing rate that is predicted by the replacement hypothesis. Neural activity in the subpopulation showing replacement is more likely to lag the observed movement, and may therefore be involved in the monitoring of the sensory consequences of a motor command. PMID:23576955
The human motor system is adaptive in two senses. It adapts to the properties of the body to enable effective control. It also adapts to different situational requirements and constraints. This thesis proposes a new neural network model of both kinds of adaptivity for the motor cortical control of human reaching movements, called SURE_REACH (sensorimotor unsupervised learning redundancy resolving control architecture). In this neural network approach, the kinematic and sensorimotor redundancy...
Renata C. M. Lima
Full Text Available Objective: To investigate the influence of hand dominance on the maintenance of gains after home-based modified constraint-induced movement therapy (mCIMT. Method: Aprevious randomized controlled trial was conducted to examine the addition of trunk restraint to the mCIMT. Twenty-two chronic stroke survivors with mild to moderate motor impairments received individual home-based mCIMT with or without trunk restraints, five times per week, three hours daily over two weeks. In this study, the participants were separated into dominant group, which had their paretic upper limb as dominant before the stroke (n=8, and non-dominant group (n=14 for analyses. The ability to perform unimanual tasks was measured by the Wolf Motor Function Test (WMFT and the Motor Activity Log (MAL, whereas the capacity to perform bimanual tasks was measured using the Bilateral Activity Assessment Scale (BAAS. Results: Analysis revealed significant positive effects on the MAL amount of use and quality of the movement scales, as well as on the BAAS scores after intervention, with no differences between groups. Both groups maintained the bimanual improvements during follow-ups (BAAS-seconds 0.1, 95% CI -10.0 to 10.0, however only the dominant group maintained the unilateral improvements (MAL-amount of use: 1.5, 95% CI 0.7 to 2.3; MAL-quality: 1.3, 95% CI 0.5 to 2.1. Conclusions: Upper limb dominance did not interfere with the acquisition of upper limb skills after mCIMT. However, the participants whose paretic upper limb was dominant demonstrated better abilities to maintain the unilateral gains. The bilateral improvements were maintained, regardless of upper limb dominance.
Eileen Yi Lee Lew
Full Text Available Early detection of movement intention could possibly minimize the delays in the activation of neuroprosthetic devices. As yet, single trial analysis using non-invasive approaches for understanding such movement preparation remains a challenging task. We studied the feasibility of predicting movement directions in self-paced upper limb center-out reaching tasks, i.e., spontaneous movements executed without an external cue that can better reflect natural motor behavior in humans. We reported results of non-invasive electroencephalography (EEG recorded from mild stroke patients and able-bodied participants. Previous studies have shown that low frequency EEG oscillations are modulated by the intent to move and therefore, can be decoded prior to the movement execution. Motivated by these results, we investigated whether slow cortical potentials (SCPs preceding movement onset can be used to classify reaching directions and evaluated the performance using 5-fold cross-validation. For able-bodied subjects, we obtained an average decoding accuracy of 76% (chance level of 25% at 62.5ms before onset using the amplitude of on-going SCPs with above chance level performances between 875ms to 437.5ms prior to onset. The decoding accuracy for the stroke patients was on average 47% with their paretic arms. Comparison of the decoding accuracy across different frequency ranges (i.e., SCPs, delta, theta, alpha and gamma yielded the best accuracy using SCPs filtered between 0.1 to 1 Hz. Across all the subjects, including stroke subjects, the best selected features were obtained mostly from the fronto-parietal regions, hence consistent with previous neurophysiological studies on arm reaching tasks. In summary, we concluded that SCPs allow the possibility of single trial decoding of reaching directions at least 312.5ms before onset of reach.
Hansen, Lennard Højbjerg
It has been an accepted precept in film theory that specific stylistic features do not express specific content. Nevertheless, it is possible to find many examples in the history of film in which stylistic features do express specific content: for instance, the circular camera movement is used...... circular camera movement. Keywords: embodied perception, embodied style, explicit narration, interpretation, style pattern, television style...
Weikart, Phyllis S.; Carlton, Elizabeth B.
This book presents activities to keep K-6 students moving in a variety of ways as they learn. The movement experiences are planned around key curriculum concepts in movement and music as well as in academic curriculum areas. The experiences develop students' basic timing, language abilities, vocabulary, concentration, planning skills, and…
Koopman, Bart H.F.J.M.
The part of (bio)mechanics that studies the interaction of forces on the human skeletal system and its effect on the resulting movement is called rigid body dynamics. Some basic concepts are presented: A mathematical formulation to describe human movement and how this relates on the mechanical loads
Fenichel, Emily, Ed.
This newsletter theme issue focuses on dance, play, and movement therapy for infants and toddlers with disabilities. Individual articles are: "Join My Dance: The Unique Movement Style of Each Infant and Toddler Can Invite Communication, Expression and Intervention" (Suzi Tortora); "Dynamic Play Therapy: An Integrated Expressive Arts Approach to…
The neural system highlighted by TMS/EEG experiments is wider with respect to the one disclosed by the TMS behavioral approach. Further studies are needed to unravel this paucity of overlap. Moreover, the understanding of these mechanisms is crucial for the comprehension of response inhibition and changes in prepared actions, which are common behaviors in everyday life.
Montanaro, Silvana Quattrocchi
Discusses stages of movement in the first 3 years of life with a philosophical dimension regarding evolutionary aspects of movement as first manifestation of "will." Describes how the early childhood environment is prepared to allow for movement and the connection between movement and brain development. Discusses the contribution of movement to…
Jackson, Stephen R.; Newport, Roger; Husain, Masud; Fowlie, Jane E.; O'Donoghue, Michael; Bajaj, Nin
Optic ataxia (OA) is generally thought of as a disorder of visually guided reaching movements that cannot be explained by any simple deficit in visual or motor processing. In this paper we offer a new perspective on optic ataxia; we argue that the popular characterisation of this disorder is misleading and is unrepresentative of the pattern of…
Rhythm is one of the fundamental elements without which music would not exist. In plays with singing, a child learns to synchronize its movements with the rhythm of music from a very early age. The skill of movement plays a major role in the learning of music and thus deserves an important place in the school curriculum. In this paper, an overview is made of the most important music pedagogues who introduced movement, and at the same time perceived its importance in learning musical conte...
Ireland’s long history of patriarchy is matched by the ongoing evolution of its women’s movements. Today’s complex, transnational feminism finds its precursor in the colonial era. The first wave of the Irish women’s movement dates from the mid-19th century, with the franchise secured for women in 1918 while still under British colonial rule. First-wave feminists played a role in the nationalist movement, but their demands were sidelined later, during the construction of a conserva...
SURAJ KUMAR SUMAN
Several of the new religious movements (NRMs) of modern times have become global movements. Among these are the Soka Gakkai of Japan; the Brahma Kumaris, Sathya Sai Baba, and Hare Krishna of India; the Tzu Chi Buddhist Compassion and Relief Society of Taiwan; and Scientology, which began in the United States in the early 1950s. In order to become global movements, NRMs must often depend heavily on one particular ethnic group as they expand beyond their home base. On arrival in new cultural co...
Tatem, Andrew J
For most of human history, populations have been relatively isolated from each other, and only recently has there been extensive contact between peoples, flora and fauna from both old and new worlds. The reach, volume and speed of modern travel are unprecedented, with human mobility increasing in high income countries by over 1000-fold since 1800. This growth is putting people at risk from the emergence of new strains of familiar diseases, and from completely new diseases, while ever more cases of the movement of both disease vectors and the diseases they carry are being seen. Pathogens and their vectors can now move further, faster and in greater numbers than ever before. Equally however, we now have access to the most detailed and comprehensive datasets on human mobility and pathogen distributions ever assembled, in order to combat these threats. This short review paper provides an overview of these datasets, with a particular focus on low income regions, and covers briefly approaches used to combine them to help us understand and control some of the negative effects of population and pathogen movements. PMID:24480992
US Fish and Wildlife Service, Department of the Interior — The Snively Basin area of the Arid Lands Ecology Reserve within the Hanford Reach National Monument was historically used to farm cereal rye (Secale cereale), among...
US Fish and Wildlife Service, Department of the Interior — Increase the diversity of the seed mix on approximately 250 acres in the Ringold Unit of the Hanford Reach National Monument (Monument) treated with aminopyralid as...
Lee, Jihyun; Pizzol, Massimo; Thomsen, Marianne
instruments to support a precautionary chemicals management system and to protect receptor’s health have also been increasing. Since 2007, the European Union adopted REACH (the Regulation on Registration, Evaluation, Authorisation and Restriction of Chemicals): REACH makes industry responsible for assessing...... environment which varies in different regions. It is also needed to include information about the sustainable level of industrial emissions in REACH reporting system; this is in order to prevent chemicals from accumulating in the environmental media and biota. New approaches and frameworks are therefore...... needed to accomplish the goals of REACH, these at the same time can decrease historical background exposure for humans and ecosystem. A comparative review about the environmental management system such as quality goals, relevant organizations and environmental monitoring systems of hazardous chemicals in...
Esslinger, Keri; Esslinger, Travis; Bagshaw, Jarad
This article describes the use of live action role-playing, or "LARPing," as a non-traditional activity that has the potential to reach students who are not interested in traditional physical education.
The analysis of the ecological Movement in France is presented: its organisation, its topics, its position with respect to the main political trends. The accent is put in particular on the antinuclear contestation
... with normal activity or have the potential to cause bodily harm. ... Stereotypic movement disorder is more common among boys than ... occur with other conditions, is unknown. Stimulant drugs such ...
... in Action Medical Editor & Editorial Advisory Board Sponsors Sponsorship Opporunities Spread the Word Shop AAP Find a Pediatrician ... Movement and Coordination Page Content Article Body At this age, your child will seem to be continually on the go— ...
Andre Menache,1 Candida Nastrucci21Antidote Europe, Perpignan, France; 2University of Rome, "Tor Vergata", Rome, ItalyAbstract: Relatively little is known about the toxicity of the many chemicals in existence today. This has prompted European Union regulatory authorities to launch a major chemicals testing program, known as Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH). Although the driving force behind REACH is ostensibly based on the precauti...
Rossi, Elena; Mitnitski, Arnold; Feldman, Anatol G
When reaching towards objects placed outside the arm workspace, the trunk assumes an active role in transport of the hand by contributing to the extent of movement while simultaneously maintaining the direction of reach. We investigated the spatial-temporal aspects of the integration of the trunk motion into reaching. Specifically, we tested the hypothesis that the efficiency ('gain') of the arm-trunk co-ordination determining the contribution of the trunk to the extent of hand movement may vary substantially with the phase of reaching. Sitting subjects made fast pointing movements towards ipsi- and a contralateral targets placed beyond the reach of the right arm so that a forward trunk motion was required to assist in transporting the hand to the target. Sight of the arm and target was blocked before the movement onset. In randomly selected trials, the trunk motion was unexpectedly prevented by an electromagnet. Subjects were instructed to make stereotypical movements whether or not the trunk was arrested. In non-perturbed trials, most subjects began to move the hand and trunk simultaneously. In trunk-blocked trials, it was impossible for the hand to cover the whole pointing distance but the hand trajectory and velocity profile initially matched those from the trials in which the trunk motion was free, approximately until the hand reached its peak velocity. The arm inter-joint co-ordination substantially changed in response to the trunk arrest at a minimal latency of 40 ms after the perturbation onset. The results suggest that when the trunk was free, the influence of the trunk motion on the hand trajectory and velocity profile was initially neutralized by appropriate changes in the arm joint angles. Only after the hand had reached its peak velocity did the trunk contribute to the extent of pointing. Previous studies suggested that the central commands underlying the transport component of arm movements are completed when the hand reaches peak velocity. These
The result of the synergy between four doctoral projects and an advanced MA-level course on Bronze Age Europe, this integrated assemblage of articles represents a variety of different subjects united by a single theme: movement. Ranging from theoretical discussion of the various responses to and ...... period of European prehistory. In so doing, the text not only addresses transmission and reception, but also the conceptualization of mobility within a world which was literally Rooted in Movement....
Diani, Mario; Bison, Ivano
This article uses empirical evidence on networks of voluntary organizations mobilizing on ethnic minority, environmental, and social exclusion issues in two British cities, to differentiate between social movement processes and other, cognate collective action dynamics. Social movement processes are identified as the building and reproducing of dense informal networks between a multiplicity of actors, sharing a collective identity, and engaged in social and/or political conflict. They are con...
Konczak, J; Borutta, M; Topka, H; Dichgans, J
Nine young infants were followed longitudinally from 4 to 15 months of age. We recorded early spontaneous movements and reaching movements to a stationary target. Time-position data of the hand (endpoint), shoulder, and elbow were collected using an optoelectronic measurement system (ELITE). We analyzed the endpoint kinematics and the intersegmental dynamics of the shoulder and elbow joint to investigate how changes in proximal torque control determined the development of hand trajectory formation. Two developmental phases of hand trajectory formation were identified: a first phase of rapid improvements between 16 and 24 weeks of age, the time of reaching onset for all infants. During that time period the number of movement units per reach and movement time decreased dramatically. In a second phase (28-64 weeks), a period of "fine-tuning" of the sensorimotor system, we saw slower, more gradual changes in the endpoint kinematics. The analysis of the underlying intersegmental joint torques revealed the following results: first, the range of muscular and motion-dependent torques (relative to body weight) did not change significantly with age. That is, early reaching was not confined by limitations in producing task-adequate levels of muscular torque. Second, improvements in the endpoint kinematics were not accomplished by minimizing amplitude of muscle and reactive torques. Third, the relative timing of muscular and motion-dependent torque peaks showed a systematic development toward an adult timing profile with increasing age. In conclusion, the development toward invariant characteristics of the hand trajectory is mirrored by concurrent changes in the control of joint forces. The acquisition of stable patterns of intersegmental coordination is not achieved by simply regulating force amplitude, but more so by modulating the correct timing of joint force production and by the system's use of reactive forces. Our findings support the view that development of reaching
Sacrey, Lori-Ann R; Travis, Scott G; Whishaw, Ian Q
Sensory control of the natural skilled movement of reaching for a food target to eat (reach-to-eat) is closely coupled to the successive phases of the movement. Control subjects visually fixate the target from hand movement onset to the point that the digits contact the food, at which point they look away. This relationship between sensory attention and limb movement suggests that whereas limb advance is under visual control, grasping, limb withdrawal, and releasing the food to the mouth is guided by somatosensation. The pattern of sensory control is altered in Parkinson's disease (PD). PD subjects may visually fixate the target for longer durations prior to movement initiation, during the grasp, and during the initial portion of hand withdrawal suggesting that vision compensates for a somatosensory impairment. Because both medication and listening to favorite musical pieces have been reported to normalize some movements in subjects with PD, the present study compared the effect of medication and listening to preferred musical pieces on sensory attention shifts from vision to somatosensation during the reach-to-eat movement. Biometric measures of eye movement and the movement of the reaching limb were collected from PD subjects and aged-matched control subjects in four conditions in their own homes: off medication, off medication with music, on medication, and on medication with music. Unmedicated PD subjects were slower to visually disengage the target after grasping it. Their disengage latency was shortened by both music and medication. Medication and music did not improve other aspects of reaching, including reaching duration and the ratings of the movement elements of limb advance, grasping, and limb withdrawal. The results are discussed in relation to the idea that one way in which medication and music may aid movement in PD by normalizing somatosensory control of forelimb movement thus reducing compensatory visual monitoring. PMID:21073905
Park, Hyeshin; Kim, Sujin; Winstein, Carolee J; Gordon, James; Schweighofer, Nicolas
Previous studies have shown that multiple sessions of reach training lead to long-term improvements in movement time and smoothness in individuals post-stroke. Yet such long-term training regimens are often difficult to implement in actual clinical settings. In this study, we evaluated the long-term and generalization effects of short-duration and intensive reach training in 16 individuals with chronic stroke and mild to moderate impairments. Participants performed 2 sessions of unassisted intensive reach training, with 600 movements per session, and with display of performance-based feedback after each movement. The participants' trunks were restrained with a belt to avoid compensatory movements. Training resulted in significant and durable (1 month) improvements in movement time (20.4% on average) and movement smoothness (22.7% on average). The largest improvements occurred in individuals with the largest initial motor impairments. In addition, training induced generalization to nontrained targets, which persisted in 1-day and in 1-month retention tests. Finally, there was a significant improvement in the Box and Block test from baseline to 1-month retention test (23% on average). Thus, short-duration and intensive reach training can lead to generalized and durable benefits in individuals with chronic stroke and mild to moderate impairments. PMID:26405046
Nabe-Nielsen, Kirsten; Jørgensen, Marie Birk; Garde, Anne Helene;
PURPOSE: Shift workers are exposed to more physical and psychosocial stressors in the working environment as compared to day workers. Despite the need for targeted prevention, it is likely that workplace interventions less frequently reach shift workers. The aim was therefore to investigate whether...... the reach of workplace interventions varied between shift workers and day workers and whether such differences could be explained by the quality of leadership exhibited at different times of the day. METHODS: We used questionnaire data from 5361 female care workers in the Danish eldercare sector. The...... workers were less likely to be reached by workplace interventions. For example, night workers less frequently reported that they had got more flexibility (OR 0.5; 95 % CI 0.3-0.7) or that they had participated in improvements of the working procedures (OR 0.6; 95 % CI 0.5-0.8). Quality of leadership to...
SURAJ KUMAR SUMAN
Full Text Available Several of the new religious movements (NRMs of modern times have become global movements. Among these are the Soka Gakkai of Japan; the Brahma Kumaris, Sathya Sai Baba, and Hare Krishna of India; the Tzu Chi Buddhist Compassion and Relief Society of Taiwan; and Scientology, which began in the United States in the early 1950s. In order to become global movements, NRMs must often depend heavily on one particular ethnic group as they expand beyond their home base. On arrival in new cultural contexts, movements are most likely to appeal to first- or second-generation economic migrants from the same ethnic background as the missionaries who brought the movement to the region in the first place. While being themselves part of the process of ever-increasing globalization, NRMs also throw light on the dynamics and mechanics of this process, on how it plays itself out. This article discusses the globalization and “glocalization” of NRMs, as well as NRMs as vehicles of a new spirituality.
Full Text Available This research aims to determine the contributions of the hip joint, lumbar and thoracic spine in the execution of Sit and Reach (SR in young Brazilians. Subjects were 195 boys from 18 to 19 years., Sit and Reach was evaluated with angular kinematic analysis through of Photogrammetry to identify the contribution of body segments in trunk flexion. A protocol was developed for evaluating reference angles that were transformed into percentage contribution of the segments. Based on the results, it was possible to create a table of classification of angles and percentages, which allowed the identification of compensation movement. It was possible to conclude that the contributions of the thoracic spine, lumbar spine and hip in performing the SR are 46.01±7.32%, 12.68±5.12% and 41.31±7.19% respectively. It is recommended that evaluations of flexion of the hip joint, thoracic and lumbar spine are performed separately by photogrammetry.
De Graaff, R.; Forbes, S.; Gennart, J.P.; Gimeno Cortes, M.J.; Hovius, H.; King, D.; Kleise, H.; Martinez Martin, C.; Montanari, L.; Pinzuti, M.; Pollack, H.; Ruggieri, P.; Thomas, M.; Walton, A.; Dmytrasz, B.
The purpose of this report is to summarise the findings of the scientific and technical work undertaken by CONCAWE to assess the feasibility and potential benefit of characterising petroleum UVCB substances (Substances of Unknown or Variable Composition, Complex reaction products or Biological Materials) beyond the recommendations issued by CONCAWE for the substance identification of petroleum substances under REACH. REACH is the European Community Regulation on chemicals and their safe use (EC 1907/2006). It deals with the Registration, Evaluation, Authorisation and Restriction of Chemical substances. The report is based on Member Company experience of the chemical analysis of petroleum UVCB substances, including analysis in support of REACH registrations undertaken in 2010. This report is structured into four main sections, namely: Section 1 which provides an introduction to the subject of petroleum UVCB substance identification including the purpose of the report, regulatory requirements, the nature of petroleum UVCB substances, and CONCAWE's guidance to Member Companies and other potential registrants. Section 2 provides a description of the capabilities of each of the analytical techniques described in the REACH Regulation. This section also includes details on the type of analytical information obtained by each technique and an evaluation of what each technique can provide for the characterisation of petroleum UVCB substances. Section 3 provides a series of case studies for six petroleum substance categories (low boiling point naphthas, kerosene, heavy fuel oils, other lubricant base oils, residual aromatic extracts and bitumens) to illustrate the value of the information derived from each analytical procedure, and provide an explanation for why some techniques are not scientifically necessary. Section 4 provides a summary of the conclusions reached from the technical investigations undertaken by CONCAWE Member Companies, and summarising the
Cressman, Erin K; Henriques, Denise Y P
Visuomotor learning results in changes in both motor and sensory systems (Cressman EK, Henriques DY. J Neurophysiol 102: 3505-3518, 2009), such that reaches are adapted and sense of felt hand position recalibrated after reaching with altered visual feedback of the hand. Moreover, visuomotor learning has been shown to generalize such that reach adaptation achieved at a trained target location can influence reaches to novel target directions (Krakauer JW, Pine ZM, Ghilardi MF, Ghez C. J Neurosci 20: 8916-8924, 2000). We looked to determine whether proprioceptive recalibration also generalizes to novel locations. Moreover, we looked to establish the relationship between reach adaptation and changes in sense of felt hand position by determining whether proprioceptive recalibration generalizes to novel targets in a similar manner as reach adaptation. On training trials, subjects reached to a single target with aligned or misaligned cursor-hand feedback, in which the cursor was either rotated or scaled in extent relative to hand movement. After reach training, subjects reached to the training target and novel targets (including targets from a second start position) without visual feedback to assess generalization of reach adaptation. Subjects then performed a proprioceptive estimation task, in which they indicated the position of their hand relative to visual reference markers placed at similar locations as the trained and novel reach targets. Results indicated that shifts in hand position generalized across novel locations, independent of reach adaptation. Thus these distinct sensory and motor generalization patterns suggest that reach adaptation and proprioceptive recalibration arise from independent error signals and that changes in one system cannot guide adjustments in the other. PMID:25972587
Couton, Philippe; López, José Julián
Opposition to utopianism on ontological and political grounds has seemingly relegated it to a potentially dangerous form of antiquated idealism. This conclusion is based on a restrictive view of utopia as excessively ordered panoptic discursive constructions. This overlooks the fact that, from its inception, movement has been central to the utopian tradition. The power of utopianism indeed resides in its ability to instantiate the tension between movement and place that has marked social transformations in the modern era. This tension continues in contemporary discussions of movement-based social processes, particularly international migration and related identity formations, such as open borders transnationalism and cosmopolitanism. Understood as such, utopia remains an ongoing and powerful, albeit problematic instrument of social and political imagination. PMID:20027697
Stienen Arno HA
Full Text Available Abstract Background In many stroke patients arm function is limited, which can be related to an abnormal coupling between shoulder and elbow joints. The extent to which this can be translated to activities of daily life (ADL, in terms of muscle activation during ADL-like movements, is rather unknown. Therefore, the present study examined the occurrence of abnormal coupling on functional, ADL-like reaching movements of chronic stroke patients by comparison with healthy persons. Methods Upward multi-joint reaching movements (20 repetitions at a self-selected speed to resemble ADL were compared in two conditions: once facilitated by arm weight compensation and once resisted to provoke a potential abnormal coupling. Changes in movement performance (joint angles and muscle activation (amplitude of activity and co-activation between conditions were compared between healthy persons and stroke patients using a repeated measures ANOVA. Results The present study showed slight changes in joint excursion and muscle activation of stroke patients due to shoulder elevation resistance during functional reach. Remarkably, in healthy persons similar changes were observed. Even the results of a sub-group of the more impaired stroke patients did not point to an abnormal coupling between shoulder elevation and elbow flexion during functional reach. Conclusions The present findings suggest that in mildly and moderately affected chronic stroke patients ADL-like arm movements are not substantially affected by abnormal synergistic coupling. In this case, it is implied that other major contributors to limitations in functional use of the arm should be identified and targeted individually in rehabilitation, to improve use of the arm in activities of daily living.
Â OnÂ 9 November the barrel toroid magnet reached its nominal field of 4 teslas, with an electrical current of 21 000 amperes (21 kA) passing through the eight superconducting coils as shown on this graph
Vestenskov, David; Drewes, Line
The conference report Guiding Warfare to Reach Sustainable Peace constitutes the primary outcome of the conference It is based on excerpts from the conference presenters and workshop discussions. Furthermore, the report contains policy recommendations and key findings, with the ambition of...
The first of five volumes for Project Teach 'n' Reach, designed to help teachers of grades 1-6 in regular classrooms to teach about various kinds of handicapping conditions, is a teacher's guide. Performance objectives, activities, worksheets, and resources are listed for the use of these teachers in the implementation of their social-science and…
Fort St. Vrain reached full power on 6 November 1981, and marks a milestone in high temperature gas cooled reactor (HTGR) technology. A review is given of its features and modifications from its construction in 1968 to the present day. It is suggested that Fort St. Vrain demonstrates the performance and safety of the HTGR concept. (U.K.)
Schinkel, J.; Fransman, W.; McDonnell, P.E.; Entink, R.K.; Tielemans, E.; Kromhout, H.
Objectives: The aim of this study was to assess the reliability of the Advanced REACH Tool (ART) by (i) studying interassessor agreement of the resulting exposure estimates generated by the ART mechanistic model, (ii) studying interassessor agreement per model parameters of the ART mechanistic model
The anti atom movement has reached many of their political claims with the German nuclear power phaseout. At the same time the government has regained the interpretive dominance with the in radioactive waste management with the new search for possible final repository sites. He anti-atom movement refuses most parts of the actual law but cannot abdicate from the responsibility of the process of site selection. The contribution shows using three actual research approaches that such a convergence is probable to occur in the future. A cooperation of anti-atom movement and the government is of high probability in the long term, but is not necessarily identical to a political acceptance.
Nathan, Ran; Getz, Wayne M; Revilla, Eloy; Holyoak, Marcel; Kadmon, Ronen; Saltz, David; Smouse, Peter E
Movement of individual organisms is fundamental to life, quilting our planet in a rich tapestry of phenomena with diverse implications for ecosystems and humans. Movement research is both plentiful and insightful, and recent methodological advances facilitate obtaining a detailed view of individual movement. Yet, we lack a general unifying paradigm, derived from first principles, which can place movement studies within a common context and advance the development of a mature scientific discipline. This introductory article to the Movement Ecology Special Feature proposes a paradigm that integrates conceptual, theoretical, methodological, and empirical frameworks for studying movement of all organisms, from microbes to trees to elephants. We introduce a conceptual framework depicting the interplay among four basic mechanistic components of organismal movement: the internal state (why move?), motion (how to move?), and navigation (when and where to move?) capacities of the individual and the external factors affecting movement. We demonstrate how the proposed framework aids the study of various taxa and movement types; promotes the formulation of hypotheses about movement; and complements existing biomechanical, cognitive, random, and optimality paradigms of movement. The proposed framework integrates eclectic research on movement into a structured paradigm and aims at providing a basis for hypothesis generation and a vehicle facilitating the understanding of the causes, mechanisms, and spatiotemporal patterns of movement and their role in various ecological and evolutionary processes. "Now we must consider in general the common reason for moving with any movement whatever." (Aristotle, De Motu Animalium, 4th century B.C.). PMID:19060196
Walton, Mark M G; Gandhi, Neeraj J
The countermanding saccade task has been used in many studies to investigate the neural mechanisms that underlie the decision to execute or restrain rapid eye movements. In this task, the presentation of a saccade target is sometimes followed by the appearance of a stop cue that indicates that the subject should cancel the planned movement. Performance has been modeled as a race between motor preparation and cancellation processes. The signal that reaches its activation threshold first determines whether a saccade is generated or cancelled. In these studies, an important parameter is the time required to process the stop cue, referred to as the stop signal reaction time (SSRT). The SSRT is estimated using statistical approaches, the validity of which has not been unequivocally established. A more direct measure of this parameter might be obtainable if a method was available to "unmask" the developing motor command. This can be accomplished by air-puff-evoked blinks, which inhibit pontine omnipause neurons that serve as an inhibitory gate for the saccadic system. In the present study, brief puffs of air were used to elicit blinks at various times while rhesus monkeys performed a countermanding saccade task. If the developing motor command has not yet been cancelled, this should trigger a saccade. When blinks occurred between approximately 50 and 200 ms after target onset, saccades were often evoked. Saccades were rarely evoked more than approximately 70 ms after stop cue onset; this value represents a behavioral evaluation of SSRT and was comparable to the estimates obtained using standard statistical approaches. When saccades occurred near the SSRT on blink trials, they were often hypometric. Furthermore, Monte Carlo simulations were performed to model the effects of blink time on the race model. Overall, the study supports the validity of the statistical methods currently in use. PMID:16760340
Like many other African countries, Kenya has a large and growing youth population. Some of the youths are mobilized into militant and political networks; one of these is the Mungiki movement. The article explores Mungiki’s combination of politics, religion and Kikuyu traditions. Using the examples...
Slepian, Michael L.; Ambady, Nalini
Cognitive scientists describe creativity as fluid thought. Drawing from findings on gesture and embodied cognition, we hypothesized that the physical experience of fluidity, relative to nonfluidity, would lead to more fluid, creative thought. Across 3 experiments, fluid arm movement led to enhanced creativity in 3 domains: creative generation,…
Session TP3 includes short reports on: (1) Modification of Goal-Directed Arm Movements During Inflight Adaptation to Microgravity; (2) Quantitative Analysis of Motion control in Long Term Microgravity; (3) Does the Centre of Gravity Remain the Stabilised Reference during Complex Human Postural Equilibrium Tasks in Weightlessness?; and (4) Arm End-Point Trajectories Under Normal and Microgravity Environments.
Carmichael, Karla D.
This paper's premise is that music, movement, and poetry are unique and creative methods to be used by the counselor in working with both children and adults. Through these media, the counselor generates material for the counseling session that may not be available through more traditional "talk therapies." The choice of music as a counseling…
Full Text Available Objectives: One major drawback of orthodontic treatment is its long duration due to slow tooth movement and the pain at the onset of treatment following application of forces. There is controversy regarding the efficacy of laser for decreasing the treatment time and pain of orthodontic treatment. The purpose of this study was to investigate the effect of low level diode laser on the rate of orthodontic tooth movement and the associated pain.Materials and Methods: In this double blind randomized controlled clinical trial, 12 or- thodontic patients referring to Shahid Beheshti School of Dentistry for first premolar ex- traction were randomly selected and allocated to gallium aluminum-arsenide laser (Ga,Al,As diode laser, 880 nm, 100 mW, 5 j/cm2, 8 points, 80 seconds, continuous mode or control group. The patients initially underwent leveling and alignment using the sectional system. Force (150 gr was applied to each canine tooth via sectional closing loops. The loops were activated every month. The rate of tooth movement and pain were monitored over the treatment period and recorded on days 1, 3, 7, 30, 33, 37, 60, 63 and 67. Two-way ANOVA was used for comparison of groups.Results: There was no significant difference in terms of tooth movement and pain scores between the irradiated and non-irradiated sides at any time point (P>0.05.Conclusion: Although laser enhanced orthodontic tooth movement in the upper jaw, we failed to provide solid evidence to support the efficacy of laser for expediting tooth move- ment or reducing the associated pain.
Cavallini, Gian Maria; Verdina, Tommaso; Forlini, Matteo; Volante, Veronica; De Maria, Michele; Torlai, Giulio; Benatti, Caterina; Delvecchio, Giancarlo
Purpose To determine the efficacy of bimanual microincision cataract surgery (B-MICS) performed by surgeons in training, evaluating clinical results, posterior capsule opacification (PCO) incidence, and clear corneal incision (CCI) architecture in a long-term follow-up and comparing results with those obtained by experienced surgeons. Patients and methods Eighty eyes of 62 patients operated on by three surgeons in training who used B-MICS technique for the first time were included in the study (Group A). Eighty eyes of 59 patients who underwent B-MICS by three experienced surgeons were included as a control group (Group B). Best corrected visual acuity, astigmatism, corneal pachymetry, and endothelial cell count were evaluated before surgery and at 1 month and 18 months after surgery. Anterior segment optical coherence tomography images were obtained to study the morphology of CCIs. PCO incidence was evaluated using EPCO2000 software. Results Out of 160 surgeries included in the study, mean best-corrected visual acuity improvement at 18 months was 0.343±0.246 logMAR for Group A, and 0.388±0.175 logMAR for Group B, respectively. We found no statistically significant induced astigmatism nor corneal pachymetry changes in either group, while we noticed a statistically significant endothelial cell loss postoperatively in both groups (P<0.05). In Group A, mean PCO score was 0.163±0.196, while for Group B, it was 0.057±0.132 (P=0.0025). Mean length and inclination of the CCIs for Group A and Group B were, respectively, 1,358±175 µm and 1,437±256 µm and 141.8°±6.4° and 148.7°±5.1°. As regards corneal architecture in the 320 CCIs considered, we found posterior wound retractions and endothelial gaps, respectively, 9.8% and 11.6% for Group A and 7.8% and 10.8% for Group B. Conclusion B-MICS performed by surgeons in training is an effective surgical technique even when assessed after a long-term follow-up. PCO incidence resulted in being higher for less
Based on the 2011 experience and Machine Development study results the performance reach of the of the LHC with 25 and 50 ns beams will be addressed for operation at 3.5 and 4 TeV. The possible scrubbing scenarios and potential intensity limitations resulting from vacuum, heating will be taken into account wherever possible. The paper mainly covers the performance of the two high luminosity regions in IR1 and IR5.
Gün, İsmet; MESTEN, Zeki
A Case Of Uterus Didelphys Reached Term and Management Abstract It is important to diagnose early in gestation the uterine abnormalities which are rarely seen or may leed to several obstetrics complications. Despite the real incidence of congenital uterine abnormalities not known so well, the incidence is 0.001 % to 10 % in whole population. The incidence of uterus didelphys is estimated as 2-8 % between them. In this case, report a pregnant with uterus didelphys who had a healthy pregnancy p...
Based on the 2011 experience and Machine Development study results, the performance reach of the LHC with 25 and 50 ns beams will be addressed for operation at 3.5 and 4 TeV. The possible scrubbing scenarios and potential intensity limitations resulting from vacuum, heating will be taken into account wherever possible. The paper mainly covers the performance of the two high luminosity regions in IR1 and IR5. (author)
Berthelot, Geoffroy,; Sedeaud, Adrien; Marck, Adrien; Antero-Jacquemin, Juliana; Schipman, Julien; Saulière, Guillaume; Marc, Andy; Desgorces, François-Denis; Toussaint, Jean-François
Limits to athletic performance have long been a topic of myth and debate. However, sport performance appears to have reached a state of stagnation in recent years, suggesting that the physical capabilities of humans and other athletic species, such as greyhounds and thoroughbreds, cannot progress indefinitely. Although the ultimate capabilities may be predictable, the exact path for the absolute maximal performance values remains difficult to assess and relies on technical innovations, sport ...
Dunnington, B C; Hayes, M. L.
Youths of today are forced to deal with the external pressures of alcohol and drug abuse on all levels-from the older youngsters across the street pressuring them to be "cool," to the "cute dog" enticing them with the glamour of being the original "party animal." Through today's mass communications, young people are exposed to negative, self-destructive attitudes. It is important, therefore, to expose them to a more positive influence and try to reach them through parental guidance, personal ...